Jonathan P. Reinemer was convicted of involuntary manslaughter yesterday by a Virginia judge who said the 19-year old's reckless driving and intoxication caused the death of four people in a violent two-car crash last November in Fairfax County.

Circuit Court Judge F. Bruce Bach immediately ordered the Falls Church man taken to jail. Bach rejected a defense request that Reinemer, who faces a 20-year maximum prison term remain free on $25,000 bond pending sentencing May 4. Reinemer will appeal the conviction, his attorney said.

"I'm certainly not precluding probation, but there would be something basically wrong with allowing him to walk out in the parking lot," Bach told a tense courtroom packed with spectators, including Reinemer's family and friends and relatives of the crash victims.

The head-on collision last Nov. 9, which killed Reinemer's three passengers and the driver of the second car, resulted in a wrenching case of mistaken identity. Two crash victims, one dead and the other alive, were confused by hospital officials for two days before grieving family members were informed of the error.

As Reinemer was frisked yesterday and led by sheriff's deputies out of the stuffy wood-paneled courtroom, his mother, who had testified in his behalf, put her head on the edge of the courtroom bench in front of her and sobbed.

In a nearby row, Edward R. O'Brien, father injured driver of the car struck by Reinemer, signed deeply, blinked back tears stared at the ceiling. "All I can think of is Larry," said the visibly shaken O'Brien. "I feel very, very relieved. I was hoping the judge would to do this."

Jessie Storey, the mother of 21-year-old Cathy Storey, whose Family first believed she too had died in the spectacular crash, embraced O'Brien. "I wanted [Reinemer] to be punished but I also felt sorry for him," said the woman whose daughter had been engaged to O'Brien's son. "Cathy's not here because she doesn't remember the accident."

In the aftermath of the collision, which occurred shortly before 2 a.m. on a curving stretch of Annandale Road, rescue and hospital personnel confused Storey and Alana Klingevbiel, one of Reinemer's passengers. The Storey family later had the body of a woman they believe to be Cathy cremated, only to discover two days later that Storey was lying unconscious in Fairfax Hospital.

Fairfax assistant prosecutor Steven A. Merrill focused his closing agrument in the two-day, nonjury trial on the deaths and injuries he said Reinemer had caused. "That's exactly why we're here today," he said.

"This defendant was . . . speeding, drinking and horsing around," said Merril, who called Reinemer's testimony that he had drunk the equivalent of five beers in the six hours before the accident "total, utter nonsense."

Reinemer, who hunched forward staring at his hands during much of the trial, testified he had left a beer party four minutes before the accident and was driving at a speed "somewhere under 50 miles per hour" -- 15 miles per hour above the posted speed limit -- when the accident occurred.

Reinemer passed a friend's car in the inside lane, swerved across the road, skidded 260 feet and slammed broadside into O'Brien's oncoming car, according to trial testimony.

State pathologist William Enos testified that a blood test performed at Fairfax Hospital showed that Reinemer was legally intoxicated six hours after the accident.

Defense attorney Robert Hall, who presented extensive testimony and exhibits including the muddy tires and rusty shock absorbers from Reinemer's car, questioned the validity of the blood test and attributed the accident to a mechanical failure of the vehicle.

Hall said the tests showed that the aborption of alcohol had been delayed by the shock of the crash and argued that because of that delay the alcohol level in Reinemer's blood could have reached its peak six hours after the accident.

Hall also noted that Reinemer's car had passed Virginia inspection a month before the accident even though the vehicle carried mismatched radial and nonradial tires, a practice outlawed by Virginia law last July.

Several defense witnesses failed to establish conclusively, however, that either the mismatched tires or a possibly faulty shock absorber could have caused Reinemer to lose control of his car.

Franklin Knapp, a Northern Virginia autombile service manager called by the defense, testified that under certain circumstances such mismatched tires could cause a driver to lose control, but did not specify what those circumstances were.

Merril contended such testimony "has absolutely nothing to do with the cause of this accident. The key violation of the whole case is alocohol."