Vernon Geberth, a nationally known homicide expert, takes a break from teaching a Practical

Somewhere in America, a man is found dead, jammed headfirst into his washing machine, with only his foot peeking out.

Is it murder? A bizarre accident? It often takes a well-trained homicide investigator to discover the truth, and few have seen a case like this.

But Vernon Geberth has seen it. The nationally known homicide expert knows how that story ends, and can recount — often with graphic crime scene photos — hundreds of other death investigations that were just as unusual. That’s why about 40 police officers from six states gathered in Lawrence this week for Geberth’s three-day training session in “Practical Homicide Investigation.” The Lawrence Police Department sent three of its own officers and hosted the seminar Monday through Wednesday at the Eldridge Hotel, 701 Massachusetts St.

The retired homicide detective and lieutenant-commander of New York City police has visited Lawrence many times before, and conducts training elsewhere in the U.S. each year. When he comes to the Midwest, he tailors his presentation to the region, Geberth said. In New York, he may talk about men falling from skyscrapers. But in Kansas, he will speak of bodies found in cornfields and deaths on railroad tracks. The man in the washing machine is the kind of suspicious death that could confront any police officer in the country.

But, as unique as each case is, Geberth preaches the same fundamentals of detective work everywhere he goes:

• Protect the integrity of the crime scene.

• Do the investigation right the first time — there won’t be another chance.

• Don’t be afraid to grab any witness off the street who looks out of place.

“If you don’t do that, you’re going to mess up the case,” he said.

In Geberth’s world, death often appears in the strangest ways, and murder is only the beginning of it. Much of today’s lesson focused on accidental deaths that caught people engaging in risky, solitary, sexual behaviors. Such cases can be shocking and puzzling to an investigator who stumbles upon the deceased person days after a fatal mishap.

Geberth, seemingly immune to horror, joked as he showed one crime scene photo after another, each more surprising than the last. It sometimes takes his Midwest audiences time to warm up to his sense of humor, Geberth said. “Sometimes, I think, they’re almost afraid to laugh.” But the veteran cop isn’t, and said he wasn’t worried about being politically correct. “I’m here to teach, not to babysit,” he said.

As a lesson in investigation and persistence, Geberth led the class through the saga of the 1985 Tim Hennis murder case, in which the young wife and two children of an Air Force captain were murdered in Fayetteville, N.C. The case frustrated investigators for years, until after more than two decades — and three separate trials — Hennis, a former Army sergeant, was sentenced to the death penalty in 2010.

The Hennis case was just one example of how challenging a homicide investigation can be. And, in some ways, times have changed for the worse since he was a detective in the South Bronx, Geberth said.

“There is no perfect investigation. It’s not a perfect world,” he said. “Right now, it’s very difficult.”

The ‘no snitch’ mentality of some neighborhoods, which today leaves homicide detectives struggling to find witnesses to a murder seen by many, has grown worse over the years, Geberth said. Kansas City, where police have seen many shootings go unsolved, is typical of many communities around the country. “People think that if you talk to the police, you’re a rat — that police are the bad guys,” Geberth said.

Another problem more prevalent today, Geberth said, was the growing number of killers attempting to stage crime scenes to look like something other than murder. Geberth attributed both problems, in part, to bad ideas spread through television, Internet videos and other media.

But the man in the washing machine could not be blamed on the media, or on anything else the police could understand. He had died by accident, after removing the interior parts from the machine, climbing inside and getting stuck. The crime scene photos showed the bruises the man suffered while trying to free himself before finally asphyxiating under his own weight.

“Why did he climb into that washing machine?” Geberth asked. “Well, we don’t know, because he isn’t here to tell us anymore.”

There are thousands more deaths to be investigated in the future, and Geberth said he feels it is his mission to spread as much experience and knowledge as possible among the next generation of homicide investigators.

“We work for God,” Geberth said, repeating a motto he’s become known for over the past three decades. “And that’s not a joke.”