ST. PETERSBURG, Fla. (WFLA) — St. Pete Police Chief Anthony Holloway’s sleepless nights began with the first murder.

“I can tell you, after that shooting, what keeps you up at night, that started keeping us up at night,” he said.

Police said Vernon Williams, 60, and Corlenzo Williams, 24, were gunned down within two miles of each other on April 10 and 12. A third victim managed to get away.

Holloway was worried the same person might come back and kill again.

“Who knows if this guy was going to commit another one,” he said. “I shouldn’t say if, but when he would commit another one.”

Homicide detectives worked round the clock to get their man, and they did.

St. Pete police tracked down Johnny Carnegie, a career criminal with a long rap sheet. Investigators found him just a short distance away.

He was in Hillsborough County behind bars after deputies arrested him on another case.

Holloway said he knew there was more to this case.

“After the first one, you’re trying to do that analysis, and then you get the second one and you’re looking at evidence and you’re going, wait a minute. Something going on here. I think that got everyone’s attention,” he said.

So, the question remains – is this the possible work of a serial killer?

The chief said he isn’t ruling it out, and said other members of law enforcement were asking the same question.

“When I called the FBI and Tampa, it was like, what can we do? What do you need? Cause I think everybody was thinking what you were thinking, we’re got to figure this out and we’ve got to figure this out now,” he said.