When the patrol car passed by, the man ducked down and tried to hide his identity from officers. That made them suspicious, so officers interviewed him, and detectives arrested him for investigation of rape.

Olympia Police Commander Tor Bjornstad said the 23-year-old David Lukas Lynch claimed to be a transient living in the woods. Police searched the woods and then found an elaborate underground bunker they believe the man slept in about 1/2 mile from the home where the attack occurred.

The box was about 4 feet high, 4 feet wide, and about 12 feet long. There was a wood stove and several books. But police found other items that made them suspicious.

"We found a knife that we believe meets the general description of the one described by the victim the night of the attack," said Det. Lt. Steve Oderman with the Olympia Police Department. "And we found general paperwork linking the suspect to the bunker inside.

Lynch was booked into the Thurston County Jail and detectives planned to take DNA samples. He will make his first court appearance Wednesday.

Utility records show that the man had lived in the neighborhood until a few months ago, Bjornstad said.

Investigators say it was just after midnight on Monday when a man armed with a knife entered through an unlocked door at a home in southeastern Olympia and raped an 11-year-old girl who had been sleeping in her bedroom.

The man ran off and officers searched the area with police dogs, but could not locate the attacker.

Bjornstad said the suspect arrested on Tuesday was spotted at about 12:15 a.m.

"A crime like this always generates a lot of concern in the community," said Bjornstad, adding that the suspect does not have a record of similar crimes. It was not known whether the attack was random or whether the girl was targeted for some reason.

Bjornstad said the girl's family was asleep during the assault and that her mother called 911 when the girl woke her up after the attack.