The 1979 Jeep that crashed on County Road in Oak Bluffs just over two weeks ago, killing 18-year-old Eric MacLean, had no seatbelts, no emergency brake, a defective steering column and a phony inspection sticker, according to Oak Bluffs police.

The car was driven by Seamus O'Brien, 18, and owned by his father, James O'Brien, 44, of Oak Bluffs. Police filed criminal complaints on Wednesday against both father and son. Neither one was arrested, but court hearings are expected to begin next week.

For the driver, a high school senior and Mr. MacLean's classmate and friend, the main charge is vehicular homicide, followed by negligent operation, a marked lanes violation, failure to wear a seatbelt and possession of false documents from the Registry of Motor Vehicles. The elder Mr. O'Brien will face charges of possessing falsified registry documents, an uninspected vehicle and defective equipment.

"Our investigation revealed that the car was inspected in June and rejected for safety malfunctions," said Oak Bluffs police chief Joseph Carter. Noted on the rejection records from Buddy Debettencourt's garage in Oak Bluffs were the lack of emergency brake and fender flares and defective steering, according to Chief Carter.

"The sticker on the vehicle didn't belong to that vehicle," said the chief. "They won't say how it got on there, but both of them have responsibilty."

Falsifying registry documents is a felony offense that could carry up to a five-year prison term, according to assistant Cape and Islands district attorney Richard Piazza. The vehicular homicide charge is a misdemeanor offense, punishable by a maximum of two and a half years in jail, he said.

Faulty steering appears to be the cause of the crash, according to Chief Carter. Alcohol or drug use was ruled out early in the investigation, and the state police accident reconstruction team was unable to determine the car's speed because there were no skid marks.

But during the investigation, certified mechanics inspected the car and discovered both a missing bolt in the steering mechanism and a missing coupling sleeve around the steering shaft. Based on the presence of hardened dirt and grime at that spot, mechanics concluded that the part "had been missing for some time," said the chief.

Plus, Seamus O'Brien told police immediately after the March 28 accident that all he remembered before the crash was that the steering began shaking. The Jeep collided with a tree, throwing both young men from the car and actually separating the body of the car from the chassis.

Chief Carter said the 1979 Jeep was a "kit car" with a fiberglass body. "It was a poorly maintained and constructed vehicle," said Chief Carter. "The whole thing had been altered."

Initially, the investigation was hampered by the lack of such basic evidence as skid marks. Also, Chief Carter said the O'Briens were not cooperative. Police were not able to interrogate Seamus O'Brien beyond their initial conversation with him at the hospital, where he was treated for minor injuries.

The accident was investigated by Oak Bluffs police officer Nicholas Curelli, Oak Bluffs detective Warren Gosson and state police Sgt. Neal Maciel. Chief Carter said he expects court proceedings against the O'Briens to begin next week.

Police notified the family of Mr. MacLean on Wednesday about the findings. Mr. MacLean was a varsity ice hockey and football player planning to join the Marine Corps in September.