Serial killers working as long-haul lorry drivers have murdered at least 500 women across America, the FBI believes.
The women – a mixture of prostitutes, hitchhikers and stranded motorists – have been killed along popular trucking routes over the past three decades.
Their bodies have been dumped on highways and at rest stops or motels popular with truckers.
Since the FBI launched a Highway Serial Killings database collecting crime information from around the US and searching for patterns, the bureau has helped solve more than two dozen murders.
US truck drivers often criss-cross huge swathes of the entire country, making it easy for homicidal ones to evade detection by police in each state, said the FBI.
“You’ve got a mobile crime scene. You can pick a girl up on the East Coast, kill her two states away and then dump her three states after that,” an investigator told the Los Angeles Times.
Many of the victims have been prostitutes and other women with “high-risk lifestyles”, the FBI stressed after revealing the hitherto unpublicised initiative to the newspaper.
“We don’t want to scare the public and make it seem like every time you stop for gas you should look over your shoulder,” said Michael Harrigan, the special agent in charge of the initiative.
However, he added that “many of these women made poor choices but that doesn’t mean they deserved to die”.
The bureau said it first saw a connection between truckers and serial killings five years ago when they were asked to help police build a case against a trucker for seven unsolved murders along Interstate 40 in Oklahoma.
In each case, the victim was a truck-stop prostitute whose body was found near the roadside.
When the FBI consulted its general crime database and the internet, it discovered around 350 similar cases, prompting the bureau to create a separate highways murder database and a full-time analyst to trawl through the figures.
FBI agents said the more than 500 cases in the database “grossly” underestimated the number of such crimes.
Investigators later identified the Oklahoma serial killer as John Williams, a 28-year-old trucker, after he and his girlfriend allegedly killed a woman they had kidnapped from a Mississippi casino.
Fearing they had been seen, the girlfriend went to police to say they had simply discovered the body, but, under questioning, Williams admitted more than a dozen murders in several states.
In the case of Buffie Rae Brawley, a truck-stop prostitute he said he bludgeoned with a truncheon-type tool used to test the pressure in lorry tires, Williams reportedly told investigators: “The second she tapped on my window, she was a dead woman.”
Although he later retracted his confession, Williams now faces the death penalty when he goes on trial in Texas for one of the murders later this year.
Another alleged serial killing trucker, Bruce Mendenhall, awaits trial in Nashville, Tennessee, for four murders after information was supplied by the FBI database.
Mendenhall, who denies the charges, was arrested after detectives started investigating a string of prostitutes founded murdered with a .22 handgun along highways in Tennessee and Georgia.
After police searched Meldenhall’s cab at the truck stop where one of the victims had been found, they allegedly found blood or DNA linking the driver to at least seven victims.
Prostitutes are not always the targets. Adam Lane, a 44-year-old North Carolina trucker, was jailed for 50 years after breaking into a family home in a Boston suburb at night.
He was found holding a knife to a 15-year-old girl as she lay in bed.
After the information was put into the FBI database, he was subsequently charged with two killings in other states.