WALDPORT (AP) - The man accused of shooting and critically wounding a police officer began to act erratically six months ago, his friends say, slipping deeper into a depression after a breakup and entertaining paranoid fantasies about being pursued by police.

An arrest warrant was issued Tuesday for David Anthony Durham, 43, on four counts including attempted aggravated murder. Police said he shot Lincoln City police Officer Steven Dodds and sped away, only stopping when his truck's tires were shredded by spiked strips left by an off-duty deputy.

The gunman fled into the wilderness surrounding Waldport's peninsula, about five miles from Siuslaw National Forest. The search for him entered its third night early Wednesday as 25-member SWAT teams armed with assault rifles searched the area.

Before the shooting Sunday night, state court records showed only minor offenses in Durham's past. He pleaded guilty to a misdemeanor prostitution charge in Portland in 1999, and had citations for speeding in 2000 and not wearing a helmet on a motorcycle in 1993.

Durham's acquaintances knew him as a friendly neighbor on rural Sauvie Island in Portland and avid landscaper who was also a volunteer firefighter. But six months ago, he was moved to "inactive service" within the Sauvie Island Fire District for unspecified emotional problems.

On Friday, co-worker Christina Cowan told the Oregonian that he didn't show up for work, didn't call, and co-workers couldn't find him.

Michael Durham told the Oregonian that his brother injured a shoulder about six months ago and began taking prescribed pain medication. That was when David Durham started having trouble "with perceiving what was real and what was not," his brother said to the newspaper.

Neighbor Nancy Meyer told KGW-TV she heard him discuss delusions about aliens and Armageddon. One of his delusions focused on law enforcement.

"He's convinced the police are going to come and get him," Meyer told the TV station. "He's packed his bags, and he's ready to go in case Armageddon happens."

"He had some bizarre behavior," co-worker Shauna Hendgen told the Oregon newspaper. "He thought people were out to get him." Her 17-year-old daughter, Hannah, said Durham was deeply upset by the end of a relationship with his girlfriend. She added that Durham thought the police and the FBI were out to get him.

When police recovered his Dodge truck, Newport police Chief Mark Miranda said they found weapons inside, though he declined to specify the type or number.

Miranda expressed confidence Tuesday that Durham would turn himself in or slip up and reveal himself.

"The longer he stays hunkered down, the more impatient he's going to get," Miranda said. "He'll do something stupid that shows us where he's at."

Dodds remained in critical condition late Tuesday, but friends told Oregon State Patrol Lt. Gregg Hastings that he was alert and improving. Michael Durham said his family wished the best for Dodds.

Police previously identified David Durham as the registered owner of the truck stopped by Dodds for speeding. State police said Durham is considered armed and dangerous, and may be accompanied by his black and white dog.

The search began after the gunman was spotted and chased by police in Newport, about 14 miles north of Waldport. Shots were fired at officers, but no one was hit.

After the truck was stopped by spike strips on the highway, he ran into a wooded area and shot at a crab fisherman on a boat in Alsea Bay, Miranda said. The fisherman was struck by shrapnel but not seriously injured.

Miranda said investigators believe the gunman mistook him for a police officer.