The gray Mercedes was weaving in and out of its lane when Tracey Blake spotted it about 10:30 that Tuesday night, she recalled yesterday, so she called 911 on her cell phone to report a drunk driver.

As police sped to the scene, Blake trailed the Mercedes, watching with increasing alarm as it veered off the road, then back on again. It hit a guardrail and kept going, Blake said. Soon the car was coming to a full stop as it negotiated curves on Woodfield Road, a two-lane highway in a rural swath of upper Montgomery County.

"Thank God," Blake told the 911 call-taker when police pulled the Mercedes over, according to a recording released by police yesterday. "I feel better. Thank God."

But the ordeal was just beginning.

As Blake, 32, drove past the Mercedes, she watched a clean-shaven man wearing a blue shirt step out of the car and walk toward the police car behind him. Then she heard the gunfire.

"Oh my God! Oh my God! They're shooting!" Blake screamed. "Oh my God!"

When the shooting stopped, the driver of the Mercedes, Dale Francis Connolly, 51, was dead with a single gunshot wound to his head -- fired by his own hand, police say. A Montgomery County police officer was bruised by a bullet that hit his torso but was stopped by a bulletproof vest.

The 911 tape released by police yesterday offered the most complete public account to date of the May 11 incident, which drew police officers from all six of Montgomery's police districts.

Maryland's medical examiner has ruled Connolly's death a suicide, said Officer John Fitzgerald, a Montgomery police spokesman. The medical examiner's office declined to provide a copy of the autopsy report, saying the office does not release information about pending investigations.

The police officers involved in the incident were not available for comment yesterday, Fitzgerald said, because the matter remains under investigation. Montgomery State's Attorney Douglas F. Gansler said his office's probe is continuing.

John Connolly, the brother of Dale Connolly, did not respond to a telephone message left at the New Market home he shared with his brother.

Blake, a Damascus resident who does clerical work for a plumbing company, described to reporters her encounter with Connolly's 1982 Mercedes after police played a recording of her 911 call, which began at 10:37 p.m., police said. Portions of the recording provided to reporters were redacted by police. Fitzgerald said those portions contained personal information about Blake.

She was within sight of Connolly's car when the shots were fired, she said.

When she heard the shots, she pulled her 2003 Mustang convertible to the side of the road and lay down across the seat, she said.

"I thought he [Connolly] was going to come to my car, get in it and shoot me," she said.

She can be heard sobbing and screaming throughout the shootings.

Officer Michael Clinton, a 29-year veteran who was weeks from retirement, pulled Connolly over at 10:56 p.m., police said. Before the officer got out of his car, Connolly opened fire with a .41-caliber Smith & Wesson revolver, police said.

Clinton fled his police cruiser and ran for cover, police said. He was unhurt, they said.

Connolly continued to fire, police said, and officers returned fire, though Connolly was obscured by darkness in a roadside field.

After about 20 minutes, police said, a final shot was heard, and Connolly's body was spotted by a Maryland State Police helicopter. Police later found his body with a bullet wound in the forehead, police said.

According to court records, Connolly has a police record dating to the 1980s.

In 1984, he was charged with malicious destruction of property in Frederick County and received one year of probation before judgment, court records show.

In 1995, he pleaded guilty in Frederick County to carrying a handgun in a vehicle on a public road and was sentenced to four months in jail and ordered to pay a $500 fine, court records show.

Natalie Vangorder, a Montgomery 911 operator, and Tracey Blake, who called police to report a motorist driving erratically, describe their experiences.