Chilling surveillance images show fatal attack on HART bus driver

In this image from the Hillsborough State Attorney’s Office accused killer Justin McGriff is seen just prior to slashing the throat of HART bus driver Thomas Dunn. Photo courtesy of Hillsborough State Attorney’s Office
In this image from the Hillsborough State Attorney’s Office accused killer Justin McGriff is seen just prior to slashing the throat of HART bus driver Thomas Dunn. Photo courtesy of Hillsborough State Attorney’s Office
Published Jun. 7, 2019

TAMPA — It seems clear that Thomas Dunn never saw the violence coming.

In the seconds before a passenger slit his throat as he steered a public bus down Nebraska Avenue, Dunn had his eyes trained on the road and his hands on the steering wheel, newly released surveillance images show. Even as the assailant drew back a knife, Dunn appeared to be unaware of what was about to happen.

Dunn's last moments alive are captured in a chilling sequence of screenshots taken from surveillance video captured by cameras on the Hillsborough Area Regional Transit Authority bus the 46-year-old Ruskin father was driving the afternoon of May 18. The photos were presented as evidence in a May 24 bail hearing for the suspect in Dunn's killing, 35-year-old Justin Ryan McGriff, and provided to the Tampa Bay Times this week by the Hillsborough State Attorney's Office.

On Thursday, a grand jury indicted McGriff on a first degree murder charge.

READ MORE: No bail for man accused in slaying of Tampa bus driver

In the screenshots, the passenger prosecutors say is McGriff can be seen sitting in the very rear of the bus, leaning an arm on the seat in front of him. He's wearing a white baseball cap and aviator sunglasses hide his eyes. There are at least seven other passengers on the bus.

McGriff makes his way to the front of the bus and stands in the aisle slightly behind Dunn, who was driving south on Nebraska. At the bail hearing, Tampa police Detective Kenneth Nightlinger testified that the bus's surveillance system caught a brief conversation between the two men.

"God bless you," McGriff said, according to the Nightlinger.

"What was that?" Dunn said.

"God bless you," he said again.

"Thank you," Dunn said. "God bless you, too."

READ MORE: Slain HART driver chose busy route because he 'loved people,' friend says

The images show the assailant swing his right arm back, a knife clearly visible in his hand, as Dunn's eyes are trained on the road and his arms and hands rest on the steering wheel. His chin is slightly raised, his neck vulnerable. At this point, the bus is traveling at 22 mph, according to a digital stamp in the screenshot.

Three images show the moment the knife makes contact with Dunn's throat. Dunn first takes his right hand off the wheel and reaches toward his neck, then his left hand. At this point, Dunn's assailant appears to be looking toward the rear of the bus.

Dunn then steered the bus to the right and began to slow down as he slumped against his seat belt, Nightlinger testified. McGriff moved to the door, the detective said, looked back at the driver, then forced his way out.

Two images from video captured by an exterior bus camera show the assailant walking away from the bus.

Police later spotted McGriff walking nearby. He kept walking when they told him to stop, police said. They chased him up an embankment toward Interstate 275, where he was shocked with a stun gun and handcuffed.

Photos presented during the bail hearing show McGriff, handcuffed and shoeless, standing beside a Tampa patrol vehicle. Another photo shows apparent blood spatter on his black Nike sneakers.

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Hillsborough Circuit Judge Joelle Ober found that there was a substantial probability that McGriff committed the crime and that there were no reasonable bail conditions sufficient to protect the community.

McGriff remained Friday in the Hillsborough County jail.

A motive for the killing remains unclear. According to an arrest report, a roommate of McGriff's told investigators he'd been behaving erratically in the days before his arrest, causing the roommate to grow fearful of him.

READ MORE: 'Now I am afraid.' Hillsborough bus drivers demand more safety precautions after murder

Contact Tony Marrero at or (813) 226-3374. Follow @tmarrerotimes.