The alleged accomplice to a home invasion in South Anchorage told police he watched his partner break through the door of a home with a revolver in hand, but he claimed he didn't know why they were there, according to a charging document filed Thursday.

Timothy Lundgren said he realized his account had inconsistencies and admitted that he was "pretty much f----d," the charges say.

Lundgren, 22, and Loren Douglas, 30, planned to rob the home of drugs and money, police said. One of three juveniles inside the home fired shots at Douglas, who died as a result, according to the charges.

The state has charged Lundgren with first-degree burglary and robbery. During a brief initial court appearance Thursday at the Anchorage jail courtroom, Lundgren said he had no savings and was appointed a public defender. He hid his face from the view of media cameras with his charges, which detail the robbery that led to the death of the man he called "Big Boy," the charges say.

Bail remained at $10,000 and a third-party custodian.

Police credit anonymous tipsters with providing information that led to Lundgren's location. Police received tips that a man named "Tim" was the second person involved in the robbery. Other callers said Lundgren suffered a head wound in the break-in and provided phone numbers.

Here's how the weeklong investigation went down, according to the charges:

Police got a call at about 4:30 a.m. on Feb. 18. A juvenile said two people broke into his home near the intersection of Country Woods Drive and Orchard Place.

Officers responded and found a large man, later identified as Douglas, lying in the front yard. Medics declared Douglas dead at the scene; an autopsy determined he suffered gunshot wounds.

Three juveniles inside the home were taken to the Anchorage Police Department for questioning. They said they were awake in the living room when there was a loud bang on the door, followed by two men shouting at them to get down.

The man in front, who is identified in the charges as Douglas, was dressed in all black, including his hat and bandana; he was brandishing a large revolver. The second man wore a red hat and red hooded sweatshirt.

"The juvenile resident fired rounds at the two men, striking Douglas multiple times in the torso and shoulder," the charges say. "Both men left the residence, leaving a significant amount of blood …"

Various amounts of four kinds of drugs were seized from the home, police reported earlier this week. Anchorage District Attorney Clint Campion previously said that if the home's occupants are charged with a crime, the information would be confidential because they're not adults.

Blood stained the floors and walls of the home, officers noted; there was splintered wood near the front door. A hat and glasses were left in the driveway. There was what officers believed to be a gunshot hole on the outside of the hat, as well as blood and hair on the inside.

The tips led police to Lundgren. At the police department, Lundgren said he was with Douglas at the Orchard Place home. He said Douglas broke through the front door with his shoulder, and corroborated the three juveniles' statements about Douglas' clothes and weapon.

"Lundgren ultimately admitted that he entered the residence but claimed he did not have any idea why they were at the residence. Lundgren acknowledged that Douglas was shot during the home invasion but he did not stop to check on Douglas," the charges say.

Lundgren told officers he'd also been shot during the robbery. He said he'd previously used a gram of heroin each day, and his girlfriend was struggling with heroin addiction.

Lundgren's rap sheet includes theft, providing false information to police and assault, among other convictions.