Police have blanketed the Seminole Heights area with additional officers. Authorities plan to hold a community meeting Monday evening with residents to talk about the killings, and how to stay safe.
"We don't have a lot of answers," Tampa interim police Chief Brian Dugan told CNN sister network HLN on Monday. "We're working leads as people call them in, we're following up on everything, but it's a very time consuming process."
An unarmed neighborhood watch group will patrol the streets to help people feel safe, reports CNN affiliate WFLA.
"It could be random acts of violence. It could be a serial killer. It could be anything at this point. But it is unusual to have this many homicides in such a small area," Ron Smith, the Tampa chapter leader of the Guardian Angels, told WFLA.
On Sunday, hundreds held candlelight vigils for the victims.
"We won't be afraid," Casimar Naiboa told the crowd, according to WFLA. "(The killer) will not get away with it. No way. We are standing right here. We are not scared of them."
His son, Anthony Naiboa, was the most recent victim.
Police said Naiboa, an autistic 20-year-old who had just graduated from Middleton High School, accidentally got on the wrong bus when he left work on October 19, and ended up in the southeast Tampa neighborhood by mistake.
Police said they believe the young man was making his way toward another stop but did not get more than 200 yards from where he was dropped off before he was shot and killed.
Naiboa was found dead 200 yards away from the home of the killer's first victim.
Benjamin Mitchell, 22, was shot and killed October 9 while waiting at a bus stop, police said.
Days later, a city employee found the body of 32-year-old Monica Hoffa. Police said they believe she was killed on October 11. Hoffa was found in a vacant parking lot half a mile from where Mitchell's body was discovered.
"When you look at the time frame, the proximity, that there is no apparent motive, that the victims are alone at the time, it's clear to me that they are all linked," police Chief Dugan said Friday.
Bryanna Fox, a former FBI profiler, said she believes the killer knows the area.
"The fact that he's so comfortable with this area, killing in a rather high traffic zone would suggest to me he is rather comfortable with this area and could be from here, have lived here in the past, works here," said Fox, an assistant professor in the University of South Florida's criminology department.
Despite the suspected connection, police have refrained from directly calling the suspect a serial killer.
"I have not used that term," Dugan told HLN on Monday. "I have purposely avoided it because I don't want people to focus on one person ... we don't have enough answers to start using labels and terms."
Tampa Mayor Bob Buckhorn also wasn't so quick to say the crimes may have been committed by 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."
After the killing of Hoffa, police encompassed the area with a SWAT team, helicopters and K-9 units. But the killer still managed to escape.
"Our officers heard the gunshots. Our officers found Anthony Naiboa out there. We have a heavy presence and this person, whoever did it, was able to sneak away," said Dugan.
Dugan expressed his exasperation and how he went from frustration to anger when dealing with the unsolved homicides.
"Someone is terrorizing the neighborhood," he said.
Police are working with Crime Stoppers and the Bureau of Alcohol, Tobacco, Firearms and Explosives in offering a $25,000 reward to anyone who can provide information leading to the arrest or conviction of the Seminole Heights killer.
Dugan urged residents to stand up to whoever is victimizing the neighborhood. The suspect should not be assumed to be black or white or even a male, he said.
"We're not going to be held hostage by whoever is doing this," he said. "We need everyone to come out of their homes at night, turn on their porch lights, and just not tolerate this type of terrorism."
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