AUBURN – A wreck in which a policeman crashed a car into a pickup last year did not cause the death of the truck’s driver, authorities said.

Local police officer Mitchell Sweetser, 42, was set to stand trial in August on a drunken driving charge stemming from the November 2007 accident. Prosecutors dropped the charge shortly before the jury was sworn in. An assistant district attorney said the state’s investigation was incomplete. He expects to recharge Sweetser.

Sweetser was placed on administrative leave without pay pending the outcome of his trial.

Prosecutors were awaiting results of an autopsy on Nathan Mark Taylor, 25, who died in June. His 2005 Nissan pickup truck was hit by Sweeter’s rented 2002 Dodge after he reportedly ran a red light in November 2007.

Taylor, whose truck was hit on the driver’s side, complained of soreness, but declined to be treated. His passenger, Amber Cyr, 20, of Hartford also declined treatment.

An autopsy recently revealed Taylor died from accidental pseudoephedrine toxicity. Pseudoephedrine is a drug found in cold remedies.

Sweetser suffered a serious head wound when he crashed through the passenger window. He also sustained a shoulder injury.

Assistant District Attorney Richard Beauchesne said his office expected to file new charges against Sweetser as soon as an investigation is completed. “There are a couple of leads we’re waiting on,” he said.

There will be no charges against Sweetser relating to Taylor’s death, he said. The Maine Office of the Chief Medical Examiner told him there was “no causal connection” between the accident and Taylor’s death in June, he said.

Beauchesne said he didn’t expect to lodge charges more serious than the count of criminal operating under the influence, a charge that his office dismissed in August. Once his investigation is complete, he would again present his case to an Androscoggin County grand jury, which he expects would hand up an indictment as it did on the earlier charge.

Although the accident occurred in this city, it was investigated by the Androscoggin County Sheriff’s Department, then referred to the Maine Attorney General’s Office because local prosecutors and local police often work together on criminal cases. Beauchesne, who is assigned to the Oxford County office of the district attorney, typically doesn’t handled cases in Androscoggin County. He was supervised in the Sweetser case by Maine’s Deputy Attorney General William Stokes.

Unattended deaths in Maine are referred to the medical examiner’s office.