Police are searching for a possible serial killer believed to have fatally shot three people over the past two weeks in Florida.
Officials believe the killings were committed by the same gunman who may have chosen the victims at random, officers said.
The latest victim was an autistic man shot dead while he walked home from work after getting on the wrong bus.
The three murdered happened blocks apart, according to local police.
Residents in the area have been advised not to walk alone at night.
"Now we have someone terrorising the neighbourhood," interim Tampa Police Chief Brian Dugan said.
He added that there is "no doubt" the crimes are linked.
Anthony Naiboa, 20, was found dead in the central Tampa neighbourhood of Seminole Heights on October 19.
The autistic charity worker was shot dead at about 8pm local time, less than a mile away from where two others were shot and killed.
Officers heard the gunshots that killed Mr Naiboa, but the suspect had fled before they arrived on scene, according to Chief Dugan.
"You can imagine the frustration of these officers to hear gunshots and not be able to find this person," Chief Dugan said.
Benjamin Mitchell, 22, was alone at a bus stop after dark when he was shot dead on 9 October.
Monica Caridad Hoffa, 32, was walking to meet a friend when she was fatally shot. She was found in a vacant lot on 13 October.
Police say the killings could be connected based on the proximity of the murders and time frame, but Mr Dugan said he was cautious about using the term serial killer, the BBC reports.
The FBI are helping local police in the investigation, and officers have released a photo of a possible suspect.
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