4th person slain in Tampa neighborhood amid search for apparent serial killer: 'This has got to stop' Police: "We are treating it as though it is related until we rule otherwise."

 -- The man “killed in cold blood” on a Tampa, Florida, street early this morning was shot from behind in a case that authorities say may be related to a string of unsolved killings that has left a community on edge.

“This has got to stop,” Tampa Mayor Bob Buckhorn said today in a press conference. “We will hunt this person down until we find them.”

Police are investigating the killing, in the Seminole Heights neighborhood, where three people were shot in 11 days in October.

“We are treating it as though it is related until we rule otherwise,” interim Tampa Police Chief Brian Dugan told reporters this morning.

Authorities have identified the latest victim as Ronald Felton, 60, who was supposed to “meet up with someone” when he was apparently targeted and killed, Dugan said.

“Someone came up from behind and shot him,” he said. “And he was left [on] the street.”

The suspect in the killing has been described as a slim black man, about 6 feet to 6 feet 2 inches tall, with a light complexion, authorities said. He was armed with a large black pistol and was last seen wearing all black clothing, according to police.

“We do have a witness that we have been discussing [what happened],” Dugan said. “When I spoke to her, she said, ‘If our officer had been five seconds earlier, he would’ve been able to stop it.’”

Police arrived “within seconds” of 911 calls, which were placed before 5 a.m., Dugan said.

‘Killed in cold blood’

Solving the killings has become personal, Buckhorn said, as he lamented having to deliver the bad news to Felton’s family.

“There will be one more family today that will be notified of a family member that was killed in cold blood,” Buckhorn said.

He added that he believes police can stop the bloodshed.

“We need to catch this killer before we need to notify one more family that one of their loved ones is dead,” Buckhorn said.

The Tampa Police Department’s Twitter account alerted the public that an “active investigation” was underway, using the hashtag #traffic.

Today’s homicide follows three unsolved killings that occurred within blocks of one another days before Halloween near a bus route used by two of the victims. Police said they believe those three killings were committed by the same person.

The other victims

The first victim was 22-year-old Benjamin Mitchell. He was shot and killed steps from his home while waiting for a bus at North 15th Street at Frierson Avenue on Oct. 9.

Two days later, 32-year-old Monica Hoffa, who police say died Oct. 11, was found slain a half-mile from Mitchell, officials confirmed.

Then on Oct. 19, Anthony Naiboa, a 20-year-old man with autism, was killed in the southeast Seminole Heights neighborhood after taking the wrong bus home from work.

All three killings remain unsolved, according to police.

Early on, police released pixelated photos of a person of interest, a slender individual wearing pants and a hooded windbreaker who was initially seen walking near one of the crime scenes and then picking up the pace to a sprint.

“We believe this is the same person we saw walking just moments earlier,” Dugan said during a news conference last month, adding that the person of interest likely has ties to the neighborhood.

“He is running in the other direction ... We believe this is the same person, once again, running away from the scene of the shooting.”

In surveillance videos subsequently released by police, the same individual is seen flipping and repeatedly staring at a cellphone in the person’s right hand.

‘Very scary and quite stressful’ for neighbors

The murder of Felton has again put the neighborhood on edge.

One resident who asked not to be named because of concerns about her safety told ABC News she and her dog were stirred awake this morning by what she thought was a neighbor taking out the trash.

Instead, it was gunfire.

“It was maybe three or four [shots],” the woman told ABC News. “I was in my bedroom, and I heard the shots, and I looked out from the living room, and there were cops all over the corner.”

“All you saw was red and blue lights flashing and the crime scene tape,” she added.

The resident said she was forced to be “on lockdown” in her home as police taped off her driveway.

She said she exchanged text messages with neighbors who, like her, were in their homes looking on as cops investigated the killing.

“It’s very scary and quite stressful,” she said. “I think we’re all on edge at this point.”