A Maryland state trooper in St. Mary's County was arrested yesterday and charged with driving under the influence of alcohol and leaving the scene of an accident after he allegedly struck and seriously injured a woman with his car in the parking lot of a bar in St. Mary's, authorities said.

Thomas Quade, 25, was arrested after allegedly striking Amy Blafour, 33, of Great Mills, about 2 a.m. in the parking lot of ABC Lounge at Hickory Hills Plaza in California with his 2000 Ford Mustang, said St. Mary's County Sheriff David D. Zylak.

Quade, who was arrested without incident at his Mechanicsville home about five hours after the incident, was booked at the St. Mary's County Sheriff's Office in Leonardtown and charged with DUI and leaving the scene of an accident, Zylak said.

At the Leonardtown station, Quade refused to take a breath test, prompting authorities to strip him of his driver's license, Zylak said. He was then turned over to his Maryland State Police barracks commander.

Quade, a two-year member of the force and a patrol trooper at the Leonardtown barracks whose duty is, among other things, patrolling for drunk drivers, has been suspended with pay, as department policy dictates.

He is expected to have a hearing within five days to determine what action will be taken next, said Cpl. Rob Moroney of the Maryland State Police barracks in Pikesville.

Quade's passenger, also a state trooper, is under investigation for his involvement, if any, in the incident. The unnamed 27-year-old, who has been on the force for six years, has not been suspended, Moroney said.

"He is facing departmental charges," Moroney said, adding that it was unclear what those charges might be. Zylak said that at the very least, the second trooper is a witness to the incident.

Zylak said that the two troopers were apparently talking with a second woman and Blafour, who stood at the passenger window of Quade's car in the bar's parking lot at Chancellors Run Road and Route 235, when Quade suddenly punched the gas, sending his car into a fishtail and striking Blafour with the car's rear panel, throwing her several feet. The second woman was not injured.

Quade and the other trooper then left the scene, apparently knowing they had hit the woman, Zylak said.

"We believe the impact was such that he would have known that he hit her," Zylak said.

Blafour sustained a broken arm and was found by responding medics lying in the parking lot of the bar. She was transported to St. Mary's County Hospital by the Lexington Park Rescue Squad and was treated for multiple non-life-threatening injuries, including facial lacerations and burn marks from rolling across the ground. She was released yesterday morning, Zylak said.

It's not believed that Quade, who was off duty at the time of the incident, intentionally struck Blafour, whom Quade apparently met that night at the bar, Zylak said.

"It was an unfortunate accident," Zylak said.

State police officials said the are taking the incident seriously.

"We don't tolerate this type of behavior from the public, let alone a trooper," Moroney said. The troopers "will be dealt with."