Updated

The reward for information about four deadly shootings in a Tampa neighborhood is now over $100,000, as the city's police chief said Tuesday he fears the next time his phone rings it could mean yet another victim.

Crimestoppers of Tampa Bay told FOX13 Tampa they have received more than 1,100 tips regarding the Seminole Heights murders since they began Oct. 9, the highest number of tips in a single case the organization has ever received.

"I am working day and night, as soon as those tips come in, to put them in the hands of detectives," Kelly McLaren, of Crimestoppers of Tampa Bay, told FOX13.

The organization has received tips from as far away as New York and Michigan, but cautioned that increases in reward money doesn't necessarily mean a rise in the number -- or quality -- of tips.

"It just depends on who has that information, and what the magic number is for that person," McLaren said.

Tampa Killing 1

Law enforcement agents investigate a fatal shooting in the Seminole Heights neighborhood in Tampa, Fla., Tuesday, Nov. 14, 2017. (Jones, Octavio/Tampa Bay Times via AP)

It's been one week since 60-year-old Ronald Felton was shot dead from behind as he crossed a street, become the fourth victim killed for no apparent reason in just over a month.

TAMPA POLICE RELEASE NEW SURVEILLANCE FOOTAGE OF SUSPECT IN FOUR SEMINOLE HEIGHTS KILLINGS

Tampa Police Chief Brian Dugan told "FOX & Friends" on Tuesday whoever is behind the crimes in the "very tight" community is "very familiar" with the area, and has so far been able to "vanish under the cover of darkness."

"The murders are very close in proximity, and that is one of the frustrating things is how are these things able to happen so close to each other," he said.

Tampa Killing 2

Law enforcement agents investigate a fatal shooting in the Seminole Heights neighborhood in Tampa, Fla., Tuesday, Nov. 14, 2017. (Jones, Octavio/Tampa Bay Times via AP)

Dugan said the possibility the killer may strike again remains a fear of his.

"When the phone rings, the first thing that goes through my mind is, 'I'm hoping they got the name and they got whoever is doing this,'" he said. The second thing that goes through my mind is, 'Do we have another one?'"

Tampa Killing 4

An FBI unit dressed in military uniforms joins the investigation on a fatal shooting in the Seminole Heights neighborhood in Tampa, Fla., Tuesday, Nov. 14, 2017. (Octavio Jones/Tampa Bay Times via AP)

Last week, police said an unidentified man who appeared on surveillance video near two of four shootings is officially a suspect.

TAMPA POLICE INVESTIGATE NEW MURDER IN SEMINOLE HEIGHTS NEIGHBORHOOD TARGETED BY SERIAL KILLER

The first video shows a man walking about the time of the first fatal shooting on Oct. 9. The second video shows the same man walking early Tuesday morning about the time of Felton's killing. The figure on both videos matched witness descriptions.

Residents and police have been on edge since Oct. 9, when 22-year-old Benjamin Mitchell was shot to death. Two days later, 32-year-old Monica Hoffa, was slain. And on Oct. 19, Anthony Naiboa, 20, was killed after taking the wrong bus home from his new job.

All of the October victims were either getting on or off a city bus, or were at a bus stop when they were shot, police said. It was unclear if Tuesday's victim was near a bus stop.

The Associated Press contributed to this report.