FILE — Andrew Douglas Olsen, 20, sits at his preliminary appearance in Yakima County Superior Court Friday, May 1, 2020. Olsen pleaded guilty to second-degree felony murder in the April 22, 2020, stabbing death of Francis M. Gallagher.

A 21-year-old Yakima man has been sentenced to 20 years in state prison for an April 2020 stabbing death.

Andrew Douglas Olsen entered a plea to second-degree felony murder in Yakima County Superior Court April 28. In his plea statement, Olsen said he was intending to cause “great bodily harm” to Francis M. Gallagher, who subsequently died because of the attack.

In return for his plea, prosecutors dismissed charges of intentional second-degree murder, first-degree assault and an unrelated charge of failing to register as a sex offender.

Olsen was out on pretrial release on the sex-offender charge at the time he stabbed Gallagher, 73, in Gallagher’s North Sixth Street apartment April 22, 2020.

Police found Gallagher in the apartment around 9 that night, and he later died at what is now Yakima Valley Memorial Hospital, according to court documents. An autopsy determined he had been stabbed more than 20 times in the left arm, left shoulder and left side of his face.

Detectives questioned Olsen, who had been convicted of indecent liberties in Kitsap County and was a Level I sex offender, because he was one of three people to go to the apartment that day, according to court documents. Police at that time took a pocketknife from Olsen’s bag as well as sampled a blood stain on his shoe, according to court documents.

In a second round of questioning, Olsen told police that he attacked Gallagher because he said Gallagher said he wanted to have sex with him and had hit him in the head with a stick when he tried to leave.

He was subsequently arrested in connection with Gallagher’s death.

Gallagher’s killing was one of 35 in Yakima County in 2020, the highest in a 40-year period,.