The grainy surveillance video, taken at different angles, shows the same person who was seen walking along a street in the historic Seminole Heights neighborhood in an earlier video released by police.
"I've come up with four reasons why this person is running," interim Tampa Police Chief Brian Dugan told reporters. "One, they may be late for dinner. Two, they're out exercising. Three, they heard gunshots and, number four, they just murdered Benjamin Mitchell."
The 22-year-old Mitchell became the first victim when he was shot and killed in front of his home on October 9.
The second victim, Monica Hoffa, 32, was killed October 11. Her body was found two days afterward by a city employee in a vacant parking lot half a mile from where Mitchell died.
Then a week ago, Anthony Naiboa, an autistic 20-year-old who had just graduated from high school, became the third victim after he accidentally got on the wrong bus after leaving work and ended up in the southeast Tampa neighborhood by mistake, police said. Authorities believe he was making his way to another bus stop but did not get more than 200 yards before he was shot and killed October 19.
'Ties to the neighborhood'
Dugan said the person in the video is not considered a suspect in the string of shootings that have residents of Seminole Heights on edge.
"He may have seen something or heard something," the chief said of the person, who is seen flipping what appears to be a cellphone in their right hand while walking.
"That might be a habit of this person," Dugan said of the phone flip. "At this point, everything is a clue, everything is a speculation."
In the video, the person is seen walking in one direction, then running the opposite way seconds after Mitchell was shot.
"We believe this person has ties to this neighborhood and we want to speak to them," Dugan said.
Police have been swarming the Tampa neighborhood amid fears that a serial killer could be on the prowl.
Tampa Mayor Bob Buckhorn said officials don't have many leads on who is behind the three shootings
. Nor do authorities have a motive for the seemingly random acts, he said.
The three victims were alone and all were found within about a half-mile of each other, Dugan said.
Police last week released a surveillance video of the same person walking in the area and asked for any information on that person.
Buckhorn said they didn't have any description of a suspect or suspects and could not even say if the suspect was a man or woman.
Officials said police have so far avoided calling the suspect a serial killer.
"We're not using the word 'serial killer' yet because we just don't have enough evidence," Buckhorn said. "We're not afraid of that word -- if we think that that's true, we'll be happy to say it. But we've got to connect the dots."
On Sunday, hundreds of residents held candlelight vigils for the victims, according to CNN affiliate WFLA
"We won't be afraid," Casimar Naiboa, the father of one victim, told the crowd. "[The killer] will not get away with it. No way. We are standing right here. We are not scared of them."
Heightened police presence
As the investigation goes on, Dugan said there will be a large police presence in Seminole Heights.
Dugan encouraged people in the neighborhood to turn on their porch lights and keep an eye on the streets. Buckhorn added that the city was cutting undergrowth, clearing alleys and adding streetlights to better get eyes on possible suspects.
"We are hunting this person down and we're not gonna stop and we're not gonna leave that neighborhood until we find him," Buckhorn said.
Dugan said the neighborhood was "on edge," particularly with Halloween trick-or-treating coming up.
"I'm not gonna let someone take over this neighborhood," Dugan said. "I'm not gonna let this community be locked inside their houses."