PORTLAND, Ore. (AP) - A Portland man charged with killing his boyfriend, whose body was found over an embankment near Dougan Falls in southwest Washington, has denied causing the man's death and says he took his own life.

The Oregonian/OregonLive reports documents show Benjamin Serrato told investigators Christopher Libert was suicidal and had asked for Serrato's help to kill himself.

Serrato says he drove his boyfriend to Dougan Falls on March 31 and then watched him walk down a trail toward the river's edge.

Authorities found Libert's body April 1 with stab wounds and gunshot wounds.

A police affidavit says Serrato initially told police he hadn't seen Libert since March 30, when they argued about his relationship with a woman.

Serrato is charged with first-degree murder.