In 1980 Alcala was tried, convicted, and sentenced to death for Samsoe's murder, but his conviction was overturned by the California Supreme Court because jurors had been improperly informed of his prior sex crimes. In 1986, after a second trial virtually identical to the first except for omission of the prior criminal record testimony, he was convicted once again, and again sentenced to death. However, a Ninth Circuit Court of Appeals panel overthrew the second conviction, in part because a witness was not allowed to support Alcala's contention that the park ranger who found Samsoe's body had been "hypnotized by police investigators."
For the third trial Alcala elected to act as his own attorney. He took the stand in his own defense, and for five hours played the roles of both interrogator and witness, asking himself questions (addressing himself as "Mr. Alcala" in a deeper-than-normal voice), and then answering them. During this bizarre self-questioning and answering session he told jurors, often in a rambling monotone, that he was at Knott's Berry Farm when Samsoe was kidnapped. He also claimed that the earrings found in his Seattle locker were his, not Samsoe's. As "proof" he showed the jury a portion of his 1978 appearance on The Dating Game, during which his earrings — if he wore any — were obscured by his shoulder-length hair. He made no significant effort to dispute the other four charges. As part of his closing argument, he played the portion of Arlo Guthrie's song "Alice's Restaurant" in which the protagonist tells a psychiatrist he wants to "kill."