The figure on both videos matched witness descriptions of a black male, 6 feet to 6-foot-2, with a thin build and light complexion.
"I want people to look at that video and look at how that person walks", says Chief Brian Dugan.
Residents and police have been on edge since October 9, when 22-year-old Benjamin Mitchell was shot to death.
Police said they believe those three killings were committed by the same person.
Wednesday, police released video of the suspect that was taken around 4:45 a.m. Tuesday, before 60-year-old Robert Felton was shot dead as he crossed the street.
Police have said there is no apparent link between the victims other than that each was out walking alone in the dark in the Seminole Heights neighborhood.
The reward has been increased to $91,000 for information leading to an arrest in the case. Still, Dugan said police are "pretty convinced" that the suspect was involved in the deaths of at least Mitchell and Felton. Police say victims were random and the suspect should be considered a serial killer. Police said Felton, a construction worker, and father of three adult children, was crossing the street when a man dressed in all black came up behind him and shot him. Felton was on his way to meet with the pastor of the local church, where he has been a volunteer for the past 10 years.
SEE IT: Tampa police release new footage of suspect in Seminole Heights killings
Police spokesman Steve Hegarty said the suspect couldn't have "gone very far, and we're talking to as many people as we can to see what they may have seen". He was last seen wearing black clothing. "When I spoke to her, she said if our officer had been five seconds earlier, he would have been able to stop it", he said.
Bryanna Fox, a criminology professor at the University of South Florida in Tampa, said it is unusual for a serial killer to use a gun. "We need someone who is thoughtful, cares, and has the heart and the fortitude and the bravery to step forward and tell us who this person is and give us the identity".
The first murder occurred on October 9, 2017.
Early on, police released pixelated photos of a person of interest, a slender individual wearing trousers and a hooded windbreaker who was initially seen walking near one of the crime scenes and then picking up the pace to a sprint. On Oct. 11, Monica Hoffa, 32, was killed and her body was found two days later.
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.
Previously, officers didn't have much to go on other than a grainy video of a person running near one of the crime scenes.
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