The case was cold last Friday.

Cops were stumped about who’d killed Imette St. Guillen six days earlier. They couldn’t exactly announce that to the world, especially with the press frenzy building at an exponential rate. Police commanders needed a new development to feed the press – after all, reporters have to fill their stories with something, and the news cycle won’t wait for actual news.

That’s why 150 uniformed cops were diverted from their normal duties and ordered to fan out across the desolate area in western Brooklyn where St. Guillen’s body had been found. With young women across the city growing nervous as their weekend social lives approached, the NYPD offered a storyline – and the images – to illustrate how hard the NYPD was working to solve the case. While detectives had already searched the area thoroughly, this search was for the television cameras. Those cops searching the Brooklyn woods might as well have been extras in a movie – although they were hardly wasting their time.

Perception has a big impact on reality, especially in terms of crime. If criminals perceive they’ll be caught, they’re less likely to strike. And if New Yorkers perceive they’re safe, they’re less likely to hibernate at home and foster a culture of fear. Police Commissioner Raymond Kelly made the right move when he decided to put on a show to show the NYPD was on the case.

Around the time of the televised search, detectives were working behind the scenes to figure out what really happened at The Falls bar in SoHo around 4 a.m. the prior Saturday morning. Witnesses initially claimed that St. Guillen left alone without incident after last call – yet the idea of a young woman being randomly snatched from the street seemed as unlikely as it did horrific. Closing time is a busy time in the trendy neighborhood. People don’t just disappear. This isn’t Mexico City.

Fortunately for all of us, police are now confident St. Guillen didn’t just disappear off the street. Within a few days, detectives expect to charge Darryl Littlejohn, a bouncer at The Falls, in the murder. Their working theory is that Littlejohn took St. Guillen to his Queens home before dumping her body a few miles away in Brooklyn. DNA tests should help fill in the blanks.

Police could have focused on Littlejohn much sooner if a family that owns the bar had been honest the whole time. Daniel Dorrian initially claimed that St. Guillen left The Falls alone after last call – creating the fear she was abducted by a stranger. But as detectives turned up the heat last weekend, he changed his tune. The new version of events has Mr. Dorrian asking Littlejohn to throw the drunk young woman out. And suddenly Mr. Dorrian remembers hearing a commotion in the hallway as the bouncer and the patron left.

If Martha Stewart should go to jail for lying to FBI agents about an obscure stock sale, what should happen to a bar owner who employs a convicted felon and then shifts his story to police during the search for a murderer who’s on the loose?

Armed with this new version of events, cops kept a close eye on Littlejohn over the weekend before hauling him in for questioning and eventually – without enough evidence to charge him with murder yet enough suspicion to want him behind bars – taking him into custody on a parole violation. Littlejohn was supposed to be home between 9 p.m. and 7 a.m., and he clearly wasn’t.

Littlejohn has been in and out of jail since 1981 when he was 16 years old, beginning with drugs and graduating to armed bank robbery in 1995. He’s used a slew of aliases over the years, plucking names from popular comic books. As Jonathan Blaze (a Ghost Rider character) he was released from prison in July 2004 after serving the legally required 6/7 of a 10-year sentence for the bank robbery. At 5′ 7″ and more than 200 pounds, he was a good pick for a bouncer. The law says bouncers can’t be ex-cons. Who exactly enforces that? Look for a new “Imette’s Law” that toughens enforcement and penalties.

Murders are down about 75% from the peak in 1990, but even two decades ago this crime would have captivated New Yorkers. The news of St. Guillen’s death broke quietly last Monday under an “exclusive” banner in the New York Post – deep inside the paper, not yet fronted on the “wood” where the story now plays out daily. Police brass were furious about the details included in the initial Post report – that St. Guillen’s hands and feet were bound, a sock stuffed down her throat and her face wrapped in tape. These details were known only to detectives and the killer.

The detectives who leaked those details were located and told to stop talking. But that didn’t stop leaks in the case. And in this case, leaks were an important tool to reassure New Yorkers the NYPD was making progress. Leaks were also a tool for detectives to drum up tips. That’s why we heard about St. Guillen arguing with a friend outside the Pioneer Bar in the Bowery, about her subsequent walk to The Falls, about her drinking two rum and cokes while sitting alone at the bar, about her looking at a piece of paper before supposedly walking out alone.

A week ago there were no suspects but lots of questions. And while there is now a suspect, plenty of questions remain: If Littlejohn is the killer, is this the first time – and why exactly did he kill this time? Why was the Dorrian family initially less than fully forthcoming about St. Guillen’s final moments in their bar? Why was a lifelong felon working security? Why wasn’t the law enforced? Is anyone enforcing the law now?

And why exactly did St. Guillen insist on staying out after her best friend went home at 3:30 a.m.? Did she plan to meet someone, hope to meet someone or just meet the wrong person?

Mr. Goldin’s column appears weekly.