In the next flashback, Lydecker tracks Laura down to her place of employment - the Bullitt and Co. ad agency. With a self-important flourish, he makes his way, unannounced, to her desk in the Stenographic Department. As he is adored by other young hopefuls in the office, he apologizes to Laura for his rough treatment of her at the Algonquin Hotel dining room:

I wish to point out that you caught me at my most difficult moment. Ordinarily, I am not without a heart...Shall I produce X-ray pictures to prove it? I wish to apologize...And now, for reasons which are too embarrassing to mention, I'd like to endorse that pen.

After signing and endorsing her pen ad, Lydecker invites her out to dinner and soon makes her his protegé. He begins to promote her burgeoning career.

During a long montage of their relationship together (with the sweetly melancholic "Laura" theme music playing softly in the background), the opportunistic, Svengali-like Waldo becomes her mentor, grooms her and ultimately takes credit for her sophisticated, cultural development and her top-level success. He "creates" and makes Laura, molding or "painting" a narrative portrait of her, during a montage of scenes. At a hairdressing salon and a clothing store, he redoes her "hairdress" and chooses more "becoming" clothes for her. He brings her to parties and receptions where he promotes her to "important clients" and "the famous and the infamous," and he furthers her career in his column. They often go out on the town to dance and dine at fashionable restaurants such as the 'El Morocco.' Only two nights a week, they remain at home cooking spaghetti:

Her career began with my endorsement of the pen. I secured other endorsements for her, introduced her to important clients. I gave her her start. But it was her own talent and imagination that enabled her to rise to the top of her profession and stay there. She had an eager mind always. She was always quick to seize upon anything that would improve her mind or her appearance. Laura had innate breeding. But she deferred to my judgment and taste. I selected a more attractive hairdress for her. I taught her what clothes were more becoming to her. Through me, she met everyone - the famous and the infamous. Her youth and beauty, her poise and charm of manner captivated them all. She had warmth, vitality. She had authentic magnetism. Wherever we went, she stood out. Men admired her. Women envied her. She became as well-known as Waldo Lydecker's walking stick and his white carnation. On Tuesday and Friday nights, we stayed home, dining quietly, listening to my records. I read my articles to her. The way she listened was more eloquent than speech. These were the best nights.

Lydecker fulfills an important intellectual and fatherly need for her, and they have a mutually-satisfying relationship in all but one respect - it is a platonic one. Laura looks elsewhere for her sexual interests with other men. Lydecker is also known to exhibit the traits of a jealous and threatened lover. Wanting to possess her, like one would possess a purchased work of art or painting, he drives off the suitors in her life - first, Jacoby, her portrait painter. Using his own trade, he skillfully writes a nasty, barbed column about the man to discredit his "affectations":

Then one Tuesday, she phoned and said she couldn't come. It didn't matter really. But when it happened again the following Friday, I was disturbed. I couldn't understand it. I felt betrayed and yet I knew Laura wouldn't betray anyone. I walked for a long time. Then, I found myself before her apartment building. The lights were on. It pleased me to know she was home 'til I saw she was not alone. Well, I waited. I wanted to see who he was. It was Jacoby who had recently painted her portrait. I never liked the man. He was so obviously conscious of looking more like an athlete than an artist. I spent the rest of the night writing a column about him. I demolished his affectations, exposed his camouflaged imitations of better painters, ridiculed his theories. I did it for her, knowing Jacoby was unworthy of her. It was a masterpiece because it was a labor of love. Naturally, she could never regard him seriously again. There were others, of course. But her own discrimination ruled them out before it became necessary for me to intercede.

Alert to anyone that would be interested in Laura, Lydecker loses Laura to the debonair, athletically-built, younger Kentuckian Shelby Carpenter at a cocktail party: "Until one night at a party at Anne Treadwell's. It was one of her usual round-ups of...non-descript characters - a corral from every strata of society." At first, Laura deflects the younger man's invitation to dance:

Laura: I'm not alone. (She looks back toward Lydecker.)
Shelby: Oh him! I thought he's still doin' the polka.
Lydecker: Excuse me, please. Yes, Betsy Ross taught it to me.

But later, in the kitchen, the "scalawag" from the South glibly sweet-talks one of the elderly cooks Louise (Kathleen Howard) to hold out some "chicken livers" for him, and to remove a spot from his suit: "I can afford a blemish on my character but not on my clothes." Then, he flirts with Laura, bragging about his own masculine qualities: "I also read palms, I cook, I swallow swords, I mend my own socks, I never eat garlic or onions. What more can you want of a man?" The spineless, parasitic gadfly, who has lost the inherited income from a Southern estate, has to "maintain the fiction" of wealth and influence. Laura asks him why he hasn't found a productive career: "Why not work?" A skillful cad, Shelby arouses her sympathies, when Lydecker appears, openly insults him, and pulls her away:

Laura, dear, I cannot stand these morons any longer. If you don't come with me this instant, I shall run amok.

Laura offers Shelby a job at Bullitt and Co., and Lydecker witnesses their handshake on it: (narrated) "I concealed my annoyance with masterly self-control. But I sensed the situation which would bear watching." Soon, Shelby and Laura become romantically involved and she is quickly taken by his charm and passion, although he lacks virtue, depth, integrity, and a work ethic.

Lydecker naturally detests Shelby. With Svengali-like domination, he tries desperately to convince Laura to drive her suitor off with a "private investigation" into the amoral man's character and background. When the dossier he has fastidiously prepared isn't convincing enough, Lydecker reveals that her fiance is a philanderer - he is two-timing her by having an affair with a young model (Diane Redfern) at the ad agency and by socializing with her own aunt:

Laura: By stooping so low, you only degrade yourself, Waldo.
Lydecker: Did you know that he almost went to jail for passing rubber checks? That he was suspected of stealing his hostess' jewels when he was a house guest in Virginia?...
Laura: What of it? I know his faults. A man can change, can't he? People are always ready to hold out a hand to slap you down but never to pick you up. All right, I'm helping Shelby. His past is his own affair. I only care about the present.
Lydecker: Speaking of the changed Mr. Carpenter in the present tense, he's now running around with a model from your own office. Her name is Diane Redfern.
Laura: I'm closer to despising you than I thought I ever would be...(after some thought) I'm sorry. I should have told you before. Shelby and I are going to be married, next week.
Lydecker: I believe you presented him with a cigarette case on his last birthday. Rather valuable, isn't it?
Laura: Where did you get it?
Lydecker: From the pawn shop where Diane Redfern took it after he gave it to her.
Laura: I don't believe it. He probably needed money and was too proud to borrow.
Lydecker: Carpenter proud? Perhaps that's why the pawn ticket was in her name.
Laura: Before this goes any further, well, I'll just... (She dials the phone for Shelby at his home.)
Lydecker: He isn't home. He's dining at Anne Treadwell's.
Laura: He can't be. He asked me to dinner.
Lydecker: He would have cancelled his appointment with her if you had accepted. He treats her rather badly these days. (Laura begins dialing Anne's number.) I'm afraid she'll say he isn't there. (She hangs up in disgust.)
Laura: Waldo? Why are you doing this?
Lydecker: For you, Laura.

To prove his point, Lydecker marches Laura to Anne's home, where they barge in and discover the two dining together. Shelby rises and smoothly tries to explain with a lame excuse:

Shelby: Hello, darling. I didn't expect to see you tonight.
Lydecker: (snorting) There you are, my dear. In a moment of supreme disaster, he's trite.
Shelby: You've been readin' too many melodramas, Waldo. I was just telling Anne about our getting married.

Feeling betrayed and spited, Laura returns Carpenter's cigarette case and promptly leaves. On Friday, the day of the murder, Laura has lunch with Diane Redfern - Lydecker continues his flashback:

What came of it I hoped to hear that night. I alternated between moods of over-optimism and over-pessimism. When the phone rang, I had a foreboding of disaster.

By phone, Laura calls to cancel her Friday dinner appointment with Lydecker - she is "dreadfully nervous" and going to the country for a few days to rethink and reconsider her marriage to the self-absorbed Shelby: "Yes, I'm afraid it's about Shelby...I've got to think this thing out for myself." In a sad reminiscence that idealizes Laura, Waldo stares straight ahead and tells the detective:

It was the last time I ever heard her voice. I was sure she had too much pride to forgive him....I shall never forgive myself for letting her become involved with Shelby. It was my fault. I should have stopped it somehow.

END OF FLASHBACKS

McPherson continues piecing together elements in the case, using her apartment as his base of operation. He visits the scene of the murder many times in the course of the film. During his second visit to Laura's apartment, he questions Laura's loyal "domestic" maid, Bessie Clary (Dorothy Adams). The unnaturally-devoted maid is upset that he is looking through Laura's letters and her private diary:

You've been readin' 'em, pawin' over them. It's a shame in the face of the dead. That's what it is. It's a shame.

Bluntly, he asks: "Who killed Laura Hunt?" The obsessively-protective maid doesn't know - she describes Laura as "sweet" and "a real fine lady" - a type of woman that the brawny, homicide cop wouldn't mix with. McPherson finds a cheap bottle of whiskey in Laura's liquor cabinet and wonders why: "She never bought cheap stuff like that, not a lady like Miss Hunt." He concludes that "somebody was with her in the apartment Friday night, someone who brought that bottle." To prevent anyone from getting "any wrong ideas" about Laura's reputation, Bessie admits that she took the bottle from the bedroom and placed it in the cabinet, and washed out the glasses and cleaned off the bottle too - and in the process destroyed some evidence.

After Bessie is excused, and Lydecker, Anne, and Shelby arrive and share a drink, Anne discusses how she might distribute Laura's possessions if she was appointed administrator of the estate. Lydecker claims a few of his own priceless art items that he "only lent" to Laura:

Lydecker: There are two or three things in here belong to me. This vase, for instance. And that, uh, clock of course, and antique fire screen. I only lent them to Laura, you know.
Anne: Oh really, Waldo.
Lydecker: Yes, really. This vase is the gem of my collection. I intend to have it back. And the clock and the screen too.
Shelby: They aren't yours. You gave them to Laura. I won't permit it.
Lydecker: Does an alleged fiance have any voice in this matter? I'll take the vase with me now and send someone to collect the other things this very day.

The shrewd cop won't permit Lydecker to leave with anything: "Nothing's leaving here except you, Lydecker."

Coming in from a hard, torrential rain one evening, McPherson finds himself alone in Laura's lavish apartment - his third visit. With the case going nowhere, the detective becomes haunted and obsessed with Laura's beautiful image - a dejected version of the 'Laura' theme music plays as the domineering portrait comes into view.

In an astonishing, sexually-charged scene of his growing infatuation and fixation for her, possessive emotions are also invoked in him - for a woman ("dame") he has never met. She is unattainable, and thus, constitutes no threat to his masculinity. McPherson smokes a cigarette, removes his overcoat and hat, and loosens his tie. Nervous in the outer room where the portrait hangs, he walks to the study, removes his jacket, and takes out Laura's love letters and diary from her desk. Worked up, he smashes his cigarette and roams into her bedroom, where he rummages through her bedroom drawers and lingerie, inhales her perfume, and peers into her mirrored closets.

Feeling slightly guilty and perverted, he returns to the living room and pours himself a drink, and then stares at her large-scale portrait - he is transfixed by it and drawn to it. He is visibly excited - and tormented, by the vision of the allegedly-deceased phantom-woman or dream lady - an ideal 'dame.'

Waldo stops by after noticing the lights on in Laura's apartment - he objects to McPherson "prying into Laura's letters," especially those from him, and he opposes McPherson's growing attraction to his protegé. Once again, McPherson takes out his hand-held pinball baseball game and plays with it, as Lydecker points out that the working-class detective is acting like a "suitor" to a woman outside his class. McPherson has secretly made a bid to buy the bewitching portrait that hangs above the mantle:

Lydecker: Haven't you any sense of privacy?
McPherson: Murder victims have no claim to privacy.
Lydecker: Have detectives who buy portraits of murder victims a claim to privacy?...McPherson, did it ever strike you that you're acting very strangely? It's a wonder you don't come here like a suitor with roses and a box of candy - drugstore candy, of course. Have you ever dreamed of Laura as your wife, by your side at the Policeman's Ball or in the bleachers? Or listening to the heroic story of how you got a silver shinbone from a gun battle with a gangster? (Frustrated with the line of questioning, McPherson shakes his puzzle and rises.) I see you have.
McPherson: Why don't you go home? I'm busy.

Lydecker once again wants to bargain for his own possessions in Laura's apartment, but McPherson refuses. The cruelly-critical columnist chides the detective before leaving and accuses him of obsessive necrophilia:

You better watch out, McPherson, or you'll end up in a psychiatric ward. I don't think they've ever had a patient who fell in love with a corpse.

A dramatic, expressive playing of Laura's theme music with strings reflects McPherson's tension and anxiety. He gazes upon the painting while clutching his drink. He falls asleep in the living room armchair under the watchful gaze of the portrait, painted by a former suitor. [It is entirely possible that the remainder of the film occurs within McPherson's dream - a fantasy tale of lethal obsession.] Then, he is uncomfortably shocked when Laura is 'reincarnated' and walks in, awakening him from dozing. She turns on the light and finds him half-sleeping in her armchair next to her portrait. He does a double-take and wipes his eyes, wondering if he is dreaming. She threatens to call the police:

Laura: What are you doing here?
McPherson: You're alive.
Laura: If you don't get out at once, I'm going to call the police.
McPherson: You are Laura Hunt, aren't you? Aren't you?
Laura: I'm going to call the police.
McPherson: I am the police.

[In the framing of the scene, the positioning of the portrait of Laura accentuates the dichotomous choice the detective must make between the real Laura and the idealized Laura. The portrait is either positioned directly to McPherson's right or between the two of them.]

Because she has been at her country house for three days (from Friday evening to Monday night), she is unaware of the news of her own slaying - she didn't read the newspapers and radio broadcasts were unavailable to her (her radio was broken). McPherson shows her the newspaper account of the murder and how everyone presumed she was dead: "Somebody was murdered in this room. Do you have any idea who it was?" Laura is horrified to realize that she is caught in the middle of a murder case. McPherson steps forward and covers the painting behind him when Laura leaves the room to take off her wet clothes. [He makes his choice for the real Laura rather than the ghostly Laura enshrined in the painting - the pre-eminence of the portrait recedes into the background for the remainder of the film.]

While changing her clothes in her bedroom, Laura finds a dress of Diane Redfern's in her closet and shows it to the detective: "It wasn't here when I left. She's one of our models. Just about my size." It dawns on both of them that the murder victim with her head blown off may belong to Diane Redfern.

Both of them also know of the illicit liaison between Redfern and Shelby: "I knew that she was in love with him. She told me so herself...at lunch last Friday. I also know that she meant nothing to Shelby. I understand him better than you do." McPherson, now both elated about her appearance but faithful to his case, presses with questions - because Laura has become a prime suspect in his eyes. He questions her about the use of her apartment while she was away. He wonders whether it was possible that Laura killed Diane Redfern out of jealousy:

McPherson: Did you know or did you suspect that he [Carpenter] was going to bring her here Friday night, Miss Hunt?
Laura: How could I? I don't know that he brought her here, and neither do you. You merely assume it.
McPherson: What other assumption is possible? Do you love this fellow Carpenter so much you risk your own safety to protect him?
Laura: (concerned) My own safety? You suspect me?
McPherson: I suspect nobody and everybody. I'm merely trying to get at the truth.
Laura: I see you have been trying to get at the truth. You've read things I never meant anyone else to look at.
McPherson: Strictly routine. I'm sorry, really.

Although she is not under arrest, she is forbidden from leaving, using the phone, or speaking to anyone. As he is departing, McPherson reveals his own personal interest in her:

If anything should happen to you this time, I wouldn't like it.

McPherson asks her to tell him the truth about her decision regarding her engagement to Shelby Carpenter, and she obliges: "I decided not to marry him." McPherson leaves with a tiny, relieved (subliminal) smile on his face.