Man convicted of killing HART bus driver sentenced to life in prison

TAMPA, Fla. - The man convicted of killing a HART bus driver three years ago was sentenced to life in prison in court Wednesday. 

Justin McGriff will serve a mandatory life sentence for first degree murder, Tampa Judge Christopher Sabella said at the sentencing hearing. 

Surveillance video from inside the bus three years ago show McGriff walk up to HART bus driver Thomas Dunn, who was behind the wheel. McGriff was heard saying, "God bless you" before fatally stabbing Dunn. 

McGriff then walked off the bus calmly as passengers scrambled to escape. 

RELATED: Man who stabbed HART bus driver found guilty of murder after jury rejects mentally ill defense

At first, McGriff went away to a State hospital after being found unfit for trial, but he later returned with his competency restored. A Tampa jury recently convicted him on the first degree murder charge. 

At the hearing, Dunn's brother was just as heartbroken as the day it happened. 

"Knowing that his kids have to grow up without him is probably the hardest part. I miss him every day," said a tearful Michael Dunn.

The victim's co-workers spoke through tears about being moving targets. Bus operator Ismael Rivera said Dunn's case hits close to home. 

"It almost happened to me, it almost happened to me in Orlando," Rivera said.

Judge Sabella also issued strong words to the court about the mental health system. 

"The common thread in all of these cases is a clear mental health issue, an underlying mental health issue that was there before some innocent person had to lose their life. The innocent person today is Thomas Dunn, and it is sad. It’s sad that our system of mental health has failed us," Sabella said.