TAMPA — Tampa police have arrested a man who they say stabbed a public bus driver to death, then fled the scene Saturday afternoon.

Justin Ryan McGriff, 35, stabbed the driver about 4 p.m., while the Hillsborough Area Regional Transit bus was moving along Nebraska Avenue between Lotus Avenue and Castle Court, just south of Linebaugh Avenue, police said in a news release.

Despite serious injuries, the unidentified driver was able to safely pull the bus over to the side of the road. The driver later died at the scene.

After the stabbing, McGriff left the bus and ran west toward Interstate 275, police said. Nebraska Avenue runs parallel to the interstate in that part of Tampa.

Officers soon spotted McGriff using a description given by witnesses of the incident.

McGriff fled from officers, police said. He was taken into custody on the shoulder of the northbound lanes of the interstate.

McGriff was initially charged with resisting arrest Sunday morning. By the afternoon, police announced that he had been charged with first-degree murder.

Officers are continuing to investigate the stabbing and as of Sunday they said they were aware of "no clear motive" for the attack. The driver's identity has not been released.

This story has been updated throughout, most recently to include the news that McGriff has been charged with murder.

Contact Megan Reeves at mreeves@tampabay.com. Follow @mareevs. Contact Kirby Wilson at (727) 893-8793 or kwilson@tampabay.com. Follow @kirbywtweets.