The man accused of supplying the Columbine High School gunmen with their semiautomatic pistol pleaded guilty today and said he bought 100 rounds of ammunition for them the night before the bloodbath.

Prosecutor Steve Jensen said there was no evidence that Mark Manes, a 22-year-old computer programmer who had attended Columbine, knew what the teenagers were planning.

Manes pleaded guilty to supplying a weapon to a minor and possession of a sawed-off shotgun. He faces one to 18 years in prison at sentencing Oct. 14.

Eric Harris, 18, and Dylan Klebold, 17, killed 12 fellow students, a teacher and themselves at Columbine on April 20.

Manes bought the TEC-DC9 at a gun show last fall and sold it to the teenagers in January for $500.

Manes also told authorities Harris asked him to purchase the ammunition, Jensen said. Manes bought two boxes of 9mm ammunition at a Kmart, then drove to Harris's house and sold them to the teenager for $25.

The ammunition purchase, not previously disclosed, was legal, Jensen said.

Robert Ransome, Manes's lawyer, said his client pleaded guilty because "the family wants to do the right thing." He said Manes was horrified by the killings.

Manes had been to shooting ranges with the gunmen. Ransome has said that it never crossed Manes's mind that they would go after their classmates.

Manes is one of two people accused of helping Harris and Klebold acquire the TEC-DC9, one of four weapons used in the rampage. Philip Duran, a pizza shop employee who worked with Harris and Klebold, is accused of introducing the teenagers to Manes.

Kip Kinkel, the teenager facing trial in shootings at Thurston High School in Springfield, Ore., blamed himself for the Columbine High School shootings, according to new records filed in the case.

Kinkel's statements to a defense psychiatrist also touched on his thoughts of suicide after the slayings of his parents on May 20, 1998, the day before the school shootings that left two dead and 22 wounded, according to a sworn statement by Lane County Deputy District Attorney Kent Mortimore.

The boy's statements were excerpted by Mortimore from a 45-page report prepared by Orin Bolstad, a psychiatrist who will testify for the defense at Kinkel's Sept. 27 trial. Kinkel, 15 at the time of the shootings, is charged with 58 counts, including four counts of aggravated murder.

In the documents, Bolstad asked Kinkel about his relationship with his parents, Bill and Faith Kinkel. "I had to be 100 percent," Kinkel said. "With my parents, if I didn't do the best, I was an embarrassment to my parents."

According to the documents, Kinkel said that when he learned of the April shootings in Littleton, Colo., "I flipped out. Started blaming myself."