In a packed courtroom in Doylestown, Judge Albert J. Cepparulo found Frank Wallace Budka, 45, guilty of vehicular homicide while under the influence of a controlled substance. Earlier, Budka pleaded guilty to numerous related charges.

Budka had smoked marijuana Jan. 29 while taking prescribed painkillers before he lost control of his car on Route 1, ramming another car and then a police cruiser that had pulled over for a traffic stop.

The impact wedged Officer Christopher Jones, 37, who was on foot, under his vehicle. The married father of three died an hour later at a hospital of head and leg injuries.

"I will say that this case is a tragedy all around," the judge said. "I did not know Officer Jones personally, but he left behind a large group of friends, fellow police officers, and family.

"It's also a tragedy for Mr. Budka, who that day was driving when he should not have been."

Jones' widow, Suzanne, cried as the judge ruled. Through a family spokesman, State Rep. Frank A. Farry (R., Bucks), she thanked law enforcement officials for "their effort and support" during the trial.

"It has been an extremely tough 91/2 months," she said. "We look forward to putting this chapter behind us."

The Jones family's many supporters came to court wearing black sweatshirts bearing the Middletown Township police logo. A smaller group appearing for Budka wore no special clothing.

Prosecutor Robert James called the outcome "the right one."

"I hope this will serve notice to others that it's not OK to smoke marijuana in the morning when they are taking their daily pills," James said.

A spokesman for the Budka family who did not give his name asked reporters "to respect our family's privacy and the Jones family's."

Defense attorney Barnaby C. Wittels echoed Cepparulo's feeling, saying the case was "a tragedy for all."

The judge told of spending "sleepless nights" wrestling with the evidence after the trial began Monday. After reading the law, he determined that both scientific and behavioral evidence should be used in deciding the case.

Wittels argued against including testimony that investigators had found Budka incoherent, confused, and with "red, glassy eyes" right after the accident, saying people in accidents normally are upset.

Tests indicated Budka had marijuana, and a substance left after it metabolizes, in his blood, at levels high enough to impair his driving. Tests showed he also had taken a normal dose of methadone prescribed for pain.

The judge said another driver whose car Budka hit, setting off the chain-reaction collision, had brought his car to a safe stop. But Budka was too impaired to handle the same situation safely.

"Mr. Budka lost control of his vehicle and went across a lane, causing the accident," Cepparulo ruled.

Budka will be sentenced after a presentencing investigation, court officials said.