Palm Harbor Fire Rescue is conducting an internal investigation following the arrest by the Pinellas Sheriff's Office of one of its firefighters, Thomas Coty Walker, on a drunken-driving charge.

PALM HARBOR — After one of its firefighters was arrested on a drunken-driving charge, Palm Harbor Fire Rescue has said it is conducting an internal investigation of the incident.

Firefighters Thomas Coty Walker, 29, was arrested at 9:23 p.m. Sunday in the driveway of his residence, according to the Sheriff’s Office.

Prior to be taken into custody for DUI, Walker, who was off duty at the time, refused to take a field sobriety test and instead ask the deputies for “professional courtesy,” the Sheriff’s Office said.

In a news release, the Sheriff’s Office said it received three 9-1-1 calls reporting that a Dodge truck was driving erratically northbound on U.S. 19 between State Road 580 and Curlew Road. According to the callers, the truck was swerving along U.S. 19 and had almost struck the highway median several times.

The deputies who were dispatched in response to the reports weren’t able to find the truck on the road. Instead, based on the licenses plate number the callers provided, the deputies went to the home address of the truck’s registered owner.

When they arrived, they found the truck parked but with its engine running and a man the Sheriff’s Office identified as Walker sitting behind the steering wheel. There was no one else in the truck.

Walker, deputies said, had glassy, bloodshot eyes and alcohol on his breath. In addition to refusing to perform the field sobriety test, Walker would not agree to provide a blood sample for alcohol-level testing.

The Sheriff’s Office issued its statement on Walker’s arrest at 12:35 p.m. Tuesday. Palm Harbor Fire Rescue issued a statement saying Walker’s DUI arrest was the subject of an internal investigation 20 minutes later.