SANTA MONICA, Calif. (AP) _ A 21-year-old songwriter faces 106 years in prison on convictions of first- degree murder and 48 counts of attempted murder stemming from an automobile rampage down a crowded Westwood sidewalk on the eve of the Summer Olympics.

Daniel Lee Young, 21, of Inglewood, seemed unconcerned with the proceedings Friday during the hour-long reading of the verdicts in the Santa Monica Superior Courtroom of Judge Jacqueline Weiss.

Young testifed he was forced to compose hit songs without compensation for 10 years under a congressional mandate and that he believed the people on the sidewalk had signed a petition to steal his songs.

''I'm a vigilante,'' he testified during the trial which began Dec. 24. ''I don't think what I did was wrong.'' Young said he wanted to go to jail ''because nobody would let me make a living at anything else.

''They stole my songs and my screenplays, so I decided to try to make a living in jail.''

He pleaded innocent and innocent by reason of insanity, and a second phase of the trial will determine if he was sane during the incident, and, if so, what his penalty should be.

In addition to the murder and attempted murder counts, Young was convicted of inflicting great bodily injury on 20 of the victims who survived, adding to his potential prison term. If sentenced to the maximum 106 years, he would be eligible for parole after 53 years.

His mother was stoic as the clerk read the verdicts of the nine woman-three man jury that had deliberated for four days. She declined to comment as she hobbled out of the court on crutches.

Young was convicted of driving his car down the crowded sidewalk in Los Angeles near the Olympic Village at UCLA last July 27, sending pedestrians flying like bowling pins.

Eileen Deutsch, 15, of New York City, was killed, and the injured included a collegiate band member, Julie Wood, who was scheduled to participate in the next day's opening ceremonies of the Olympic Games.

Deputy Public Defender Irwin Pransky contended that Young ''is really psychotic,'' and said during closing arguments that Young was guilty of second-degree murder and assault with a deadly weapon.

Among other things, Young believed he wrote hit songs for pop stars Michael Jackson and Prince and that he wrote the sound track for the movie ''Ghostbusters,'' Pransky said.

Police said Young told them he was angry with officers because of an alleged beating by police that was never substantiated.

Young's family said he was under psychiatric care and taking an anti- depressant drug when he was arrested. He later was ruled mentally competent to stand trial and capable of understanding proceedings against him.