The rest of the show deals mostly with Cooper learning what he can about Laura, while Lynch and Frost dangle suspicion over the heads of different male characters. There are very few men in Twin Peaks who are not "obviously the killer" at some point during the series. I was sure the killer was James Hurley until the end of the pilot, when Bobby and Mike started howling like rabid fiends in their jail cell, and now that ponytailed trucker Leo Johnson seems a sure fit. But later on it will clearly be established that the wacky Dr. Jacoby did it, or that show salesman with one arm, or that long haired, crazy looking guy named Bob (who only appears in the visions of Sarah Palmer and dreams of Dale Cooper), or that lady with the log... it could be anyone!
This atmosphere of suspicion can really get into your head. It is a town-wide version of the classic murder mystery, set up in a claustrophobic room full of different characters, one of which is the real killer. At one point, I was entertaining the idea that dimwitted deputy Andy was actually the real killer, because that would be truly unexpected.
Over time, as the mystery remains unsolved, the audience is surrounded by people who are revealed to have reprehensible secrets, but ultimately only one of these people killed Laura. Unless of course there is a massive, town-wide cult that all joined in to kill her together like in The Wicker Man... and we're back to square one again.
Meanwhile, Laura is revealed to have been full of secrets, herself. The coroner's report indicates that not only was there cocaine in her bloodstream (which had been set up in the pilot), but that she had sexual relations with at least three men in the twelve hours before she died. James Hurley is quickly cleared of suspicion (at least for the time being) when questioned by Cooper and Truman. But Bobby and Mike are allowed to go with nothing more than a "make-sure-you-get-your-stories-straight-before-we-talk" bluff from Agent Cooper, though he does warn them not to go after James in retaliation for sleeping with Laura (who was dating Bobby).
Cooper operates on a blend of intuition and deductive reasoning: his methods are very instinct-driven, and ultimately prove to work. He senses that both James Hurley and Bobby Briggs are innocent of the crime, even though they both stood as prime suspects with weak or absent alibis.
Several other classic moments unfold during the course of this episode (for instance, the fish in the percolator). I was struck when Lucy proved her habit of over-describing things useful by explaining the sound of a long-distance phone call in 1990: "It has that open air sound, you know, where it sounds like wind blowing. Like wind blowing through trees."