The reward for information leading to the gunman behind a string of killings in Tampa, Florida, was hiked to $100,000 on Thursday as police beefed up patrols in the targeted neighborhood and sifted through a mountain of tips.

A suspect has already been caught on video twice. The chilling footage captured near two of the four fatal shootings shows a tall, thin man in a hooded jacket or sweatshirt walking nonchalantly down the street with a distinctive gait.

"It's very clear this person can flip a switch and go out and murder someone," Tampa Police Chief Brian Dugan said Wednesday when police released the second video clip in hopes that someone would recognize the shooter.

The footage was found shortly after Ronald Felton, 60, was ambushed and gunned down on his way to feed the homeless at a church Tuesday morning.

The shooting happened just blocks from a memorial for the victims of three other shootings that police believe are linked: Benjamin Mitchell, 22, killed Oct. 9; Monica Hoffa, 32, found dead Oct. 13; and Anthony Naiboa, 20, killed Oct. 19.

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. After Felton was killed, police locked down the area and went from house to house but did not find a suspect.

Gov. Rick Scott has directed the Florida Highway Patrol to send more officers to Tampa to patrol the neighborhood until the killer is caught. And a local restaurant owner chipped in $9,000 on Thursday to bring the total reward to $100,000.