Residents of northern Colorado are being warned by a professor who is an expert in criminology to start carrying weapons.
"I'm not going to be out there and not armed," said Don Lindley, a longtime professor at Regis University who has a doctorate in criminology and has studied a number of serial killers.
Advertisement - story continues below
He spoke with the Fort Collins Coloradoan as police in several jurisdictions investigated a series of shootings that may be the work of a serial killer.
On April 22, Cori Romero of Milliken was driving on Interstate 25 around 11 p.m. when she was shot through the neck. She survived. Then on May 18 Windsor resident John Jacoby, 47, was fatally shot while he was riding his bike only a few miles from where Romero was attacked. On June 3, Loveland resident Bill Connelle, 65, was shot and killed.
TRENDING: Mysteries of marriage
Lindley said he believes the attacker will try to strike again, and there's only one option: self-defense.
Advertisement - story continues below
"I know a lot of citizens have this belief that just because they are a nice person that no one will hurt them. That's not true," he told the Fort Collins newspaper. "We are all very vulnerable. If we are going to be in charge of our own safety, we need to have our own tools to protect our safety. … We need to be armed."
He cautioned people should do it right.
"If you look around and see all of these gun stores teaching firearms training, there is a reason for that," he said. 'Law enforcement does a hell of a job, but they can't protect everyone."
Investigators hunting for clues in the shootings include local police department representatives as well as the FBI, and the first two shootings already have been linked.
Lindley told the newspaper he expects the attacker is watching for the next chance.
Advertisement - story continues below
"These are crimes of opportunity and it doesn't matter if these people would have been a priest or nun, they would have been shot," he said.
Lindley, who in addition to his academic work has decades of experience both in the military and in police work, said these "types of people usually don't stop."
"Whether one person or a copycat, they will not wait very long to do it again. I think this person will do it until they get arrested," he said.