CHARLESTON, W.Va. -- A man toting axes, a shovel and bleach when he was killed by a female escort he met online had been stopped, interviewed or investigated by police in at least 20 states and is being looked into for possible links to unsolved disappearances or slayings of women around the U.S., authorities said Monday.

West Virginia authorities are trying to circulate information to see if Neal Falls, of Springfield, Oregon, can be linked to any other crimes against women in the U.S. Police say Falls was fatally shot July 18 as he attacked and choked the escort in Charleston, West Virginia, and she grabbed his handgun off the ground and fired it.

Police found axes, knives, handcuffs, a shovel, bleach and other items in Falls' car, raising suspicions this wasn't the first time he had attacked a woman.

"The fact that he was 45 years old, and carrying tools like he was, and committing a crime that was so organized and so violent, it's unlikely that this was his first violent crime," Lt. Steve Cooper, Charleston police chief of detectives, said.

Cooper said Falls had a list of 10 other women in his pocket. Nine were in West Virginia; one was across the U.S. in San Diego. Similar to the Charleston woman, whom police are calling Heather, all were escorts active online, he said. They are all still alive, he said.

Heather had a separated shoulder, broken vertebrae, strangulation marks around her throat and other injuries, Cooper said.

So far, no history of major crimes in Falls' record has surfaced. However, police said records do show that authorities in as many as 20 states -- including Arizona, Kentucky and Virginia -- had interactions with Falls such as stopping him, running his vehicle's license plate or checking his federal Social Security number.

Charleston police have notified southern Nevada authorities, who said they are investigating Falls' possible involvement in a series of killings long believed to be connected. Police have said Falls rented a room in the Las Vegas suburb of Henderson when four prostitutes went missing in the area. In three cases, young women working as prostitutes went missing and were found dismembered on the side of a road.

Henderson police spokeswoman Michelle French said they are checking into any possible Falls connection to the 2005 disappearance of 21-year-old Lindsay Harris. She was the subject of a massive search, and her family from central New York helped comb the desert area where her rental car was last seen 30 minutes from the Las Vegas Strip. The case appeared on an episode of the TV show "America's Most Wanted." Leg parts were identified as hers through DNA testing three years after they were found off Interstate 55 near Springfield, Illinois, more than 1,600 miles (2,575 kilometres) away.

Las Vegas police confirmed they're investigating the death of 25-year-old Misty Saens, whose partial remains were wrapped in plastic and cloth and were found off a road near the Red Rock Canyon National Conservation Area in 2003.

North Las Vegas police said detectives are searching for 21-year-old Jessica Foster, who was reported missing from the Vegas suburb in 2006. A fourth woman was reported missing from Vegas in 2003, and her torso was found wrapped in plastic near the Nevada-California border.

Cooper said West Virginia police have also been communicating with authorities in the small southern Ohio city of Chillicothe, where four women died in suspicious circumstances and two others are missing. He said there has been no evidence yet placing Falls there, but it's been considered because of the proximity to West Virginia -- less than a two-hour drive away.

Cooper said police are still gathering information on Falls. It appears he was staying in his car, where he kept a pillow and sleeping bag, Cooper said.

"He had no cash, no credit cards," Cooper said. "It's a mystery how he had travelled across the country to us right now. There's something that we haven't discovered yet."

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Sewell reported from Cincinnati. Associated Press writer Sally Ho in Las Vegas contributed to this report.

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This story has been corrected to show Cooper said the man had contact with police in upward of 20 states, not in 20 states.