State seeks death for man accused in Tampa bus driver's slaying

TAMPA — Prosecutors will seek a death sentence for a man accused of stabbing to death a Tampa bus driver.

The office of Hillsborough State Attorney Andrew Warren filed a notice of intent to seek the death penalty late last month in the case of Justin Ryan McGriff, who is charged with first-degree murder in the May 18 killing of Thomas Dunn.

Surveillance videos captured the attack on Dunn, 46, whose throat was cut as he steered a Hillsborough Area Regional Transit bus along N Nebraska Avenue.

Photographs from the recording, which were used as evidence in a pretrial detetion hearing in May, show a man, whom police identified as McGriff sitting in the rear of the bus. He removes something from his pants pocket, according to court testimony, then walks forward and stands behind the driver.

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"God bless you," McGriff said, according to court testimony.

"What was that?" Dunn asked.

"God bless you," he repeated.

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

After that, McGriff lunged forward, slitting Dunn's throat, according to police.

Dunn steered the bus to the right and hit the brakes as he collapsed. As passengers panicked, McGriff forced his way out the bus door, police said. Officers later spotted him nearby and arrested him.

In June, McGriff's public defenders suggested that he may be mentally ill. One of McGriff's roommates told police that his behavior in the days before his arrest was erratic, according to a court document.

A judge appointed two doctors to determine whether he is competent to proceed toward trial. If he is declared incompetent, he would likely spend time in a state hospital before the case against him could continue.

Warren, who became the county's top prosecutor in 2017, has been reluctant to seek death sentences in cases where a defendant's mental health is in question.

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If McGriff is ultimately convicted of murder, prosecutors will have to prove the existence of at least one "aggravating circumstance" before a jury weighs whether a death sentence is justified. Prosecutors cited four such circumstances in Dunn's slaying, among them that the crime was "especially heinous, atrocious, or cruel" and that it was done in a "cold, calculated, and premeditated manner."

The law requires that a unanimous jury recommendation to impose a death sentence. Otherwise, the penalty is life in prison.

Contact Dan Sullivan at dsullivan@tampabay.com. Follow @TimesDan.