WICHITA, Kan. He answers his cell phone, “Homicide.”

A lecture hall filled with 100 students looks on.

Wichita, Kan., police Lt. Ken Landwehr pauses just a few seconds to talk quietly, then puts the phone away.

He delivers his lecture dressed in a crisp white shirt, tie and slacks. A gun and badge hang at his waist.

By day, Landwehr directs perhaps the nation’s best-known serial killer investigation _ the hunt for BTK, the codename for the notorious Kansas serial killer sought in connection to eight homicides between 1974 and 1986. Each Tuesday night, he teaches a three-hour class titled Serial Killers.

“Wichita is a much easier hunting ground,” he tells his students. “It’s much easier to be anonymous. He thinks it is the sexual deviance of many killers that catches the attention of the media.”

“Serial killers like Al Capone are just gangsters,” he said. “They don’t pique as much interest in the long run.”

He outlines, with the aid of PowerPoint, some of the challenges facing investigations, such as managing large amounts of information, media pressure and lack of experience.

Investigators in the Midwest were not always prepared to handle such cases, he says.

“In the early 1970s and even the 1980s it was difficult,” he tells his students. “We were not very aware of serial killers, especially in the Midwest. We didn’t have a lot of that. A lot of places had a lack of experience with how to deal with it.”

Police may use strategies such as forming task forces and releasing information But he dislikes when the media use profilers.

“The experts talk about what the press knows,” he says. “And they know very little of the information.”

He has taught this course for five years. He also teaches classes on profiling and sex crimes at the university.

He was assigned to work full time on the case in 1984 and has investigated it ever since.

“I stopped because it’s unsolved,” he says. “I decided to take it out. I did one lecture on it and showed a little of the crime scene.”

There are five manners of death, he tells the students: natural, accidental, suicide, homicide and undetermined.

Then he returns to his lecture, and the content is grim. He spares his students nothing, including several graphic photos of decomposing bodies.

Next he reviews the crime scene from the 1998 murder and sexual assault of Regina Gray, 28, in her home after she attended a catechism class. The first shots he flashes across the screen are of Gray’s front and back doors.

What do you notice? he asks.

The front door is open, she let him in, they answer.

Then come the disturbing crime scene photos.

He lists several men who were suspects and details how her neighbor, Stanley Elms, was connected to the case.

DNA samples linked him. He told his mother-in-law details only the killer would know, and chose a victim too close to his home, Landwehr says. He was one stupid guy.

Elms was convicted of Gray’s murder. “Remember Stanley. Remember Regina,” Landwehr says as he closes the class. “I’ll see you next week.”