(CNN) -- "He pulled a gun on me! He was going to kill me!"
Those are the chilling words caught in the background of a 911 call placed earlier this month after a woman's face-off with an attacker who tried to rape her, pointing a 9 mm gun to her chest.
The victim, who is being called "Heather" by investigators, fought back so hard, police in Charleston, West Virginia, said, that her attacker lost control of his gun.
Heather grabbed the weapon and blindly shot it, killing 45-year old Neal Falls in self-defense, police said.
Based on "geography and evidence," police said Falls may have been involved in crimes against women in Illinois, Nevada and Oregon.
Heather suffered a broken vertebra and a separated shoulder in her struggle with Falls, who police say she met after connecting via the escort section of backpage.com.
Heather was not charged in the incident, according to Lt. Steve Cooper, chief of detectives of the Charleston, West Virginia, Police Department.
Because the offender died during the crime, "our case is closed," Cooper said.
While the West Virginia part of the story might be over, what police discovered in the trunk of Falls' car has investigators in other states wondering if he could be linked to some of their unsolved cases.
Cooper said Falls had four sets of handcuffs, an ax, a machete, bulletproof vests, knives, a box cutter, a large container of bleach, and a large number of trash bags. Falls also had a list of about 10 women -- all escorts in West Virginia -- along with their ages and phone numbers.
Those women are all alive and have not had any previous contact with Falls, Cooper said.
In 2005, Falls lived in Las Vegas, the same year four women working as escorts in the area disappeared. Their dismembered bodies were later discovered in Illinois.
"Our role is simply to share DNA, other crime scene information, and witness and victim information with any other agency that wants to compare their cases with this one," Cooper said.
Authorities have ruled out a connection between Falls and unsolved cases in Ohio, where six women have gone missing or turned up dead in a little more than a year.
"There is nothing whatsoever that can tie him to the missing women in Chillicothe," said Lt. Michael E. Preston, spokesman for Ross County Sheriff's Office.
Representatives from Henderson, Nevada, and Illinois State Police have confirmed they are working with the Charleston authorities to further their investigations.
Falls' car had an Oregon license plate, and he is believed to have lived in the state for a time, though police couldn't say for sure when he was last a resident.
CNN spoke to a woman in Eugene, Oregon, who said she is Falls' sister. She said she wants nothing to do with her brother and the family will have no further comment.
Falls' former landlord told CNN affiliate KVAL that Falls lived at her house in 2010. The woman, who asked to be identified only as Pauline, said she evicted Falls after one year because his strange behavior made her uncomfortable.
"The first thing that he did that was a little odd was that he immediately changed the deadbolt to his own room so that only he had a key," Pauline told KVAL. "He said he had guns and weapons and that he was a security guard."
Springfield, Oregon, Police Sgt. Rich Charboneau said his department had some contact with Falls during the last few years for minor offenses like traffic tickets and a dog at large.
Falls also filed a complaint against someone else for trespassing on his property.
"Little creepy, very tightly lipped and not a chummy guy, definitely not a chummy guy," Pauline said. "Somebody who doesn't like to be exposed."
Though there are no open murder investigations in Springfield, police have assigned a homicide detective to work as a liaison with officials in West Virginia, Charboneau said.
CNN has reached out to the Las Vegas Police Department. There has not yet been a response.
CNN's Chuck Johnston, AnneClaire Stapleton, Camille Cava, Julia Talanova, and Janet DiGiacomo contributed to this report.