A Florida man allegedly killed his 5-year-old daughter early Thursday morning by throwing her off a bridge in front of a police officer who tried to stop him, Bay News 9 reported.

John Nicholas Jonchuck Jr. was headed southbound in St. Petersburg on the Dick Misener Bridge at around midnight when he sped past a police officer at 100 miles per hour. The officer pursued the Chrysler PT Cruiser, but Jonchuck stopped the vehicle at the top of the bridge, exited with his daughter and threw her over the railing, St. Petersburg Police Chief Anthony Holloway told Bay News 9.

The child, Phoebe Jonchuck, landed in the Tampa Bay about 60 feet below. Dive teams recovered her from the water about a mile from where she went in, but she was pronounced dead at a local hospital. Investigators do not know yet if she was alive before she was thrown off the bridge.

The 25-year-old father returned to his vehicle and sped off. Police eventually stopped him in Manatee County as he headed southbound in a northbound lane on Interstate 75.

As of Thursday morning, it's still unclear why Jonchuck allegedly killed his daughter, whom he had custody of. The officer who saw him on the bridge said the father uttered something but did not hear what he said.

"He did not [give any indications why this happened]," Holloway told Bay News 9. "Again, when he got out the car [Jonchuck] said something but the officer has no idea what he said."

As police questioned the father, investigators have learned he lives with his parents in Tampa and has prior arrests, including one for domestic battery in 2008 and one for a DUI in 2013, WTSP reported.

He filed a domestic violence charge against Phoebe's mother in December, but it was thrown out in court.

Police said at this time Jonchuck is not cooperating. He remains held on charges of first degree murder, aggravated fleeing and eluding and aggravated assault with a motor vehicle on a law enforcement officer.