EVERETT — Everett police investigators are asking for the public’s help to identify a man who may have witnessed a fatal stabbing in August.

Derrick Everson, 21, was killed Aug. 20 in the 7800 block of Broadway. Police arrested David Kopp, 19, a few hours after the slaying. Kopp has been charged with first-degree murder in connection with the slaying.

Investigators believe Kopp attacked Everson with a butterfly knife and stabbed him 25 times, court papers said. Kopp told detectives Everson was irritating him while they were smoking marijuana and drinking beer with two other men, court documents said.

Everett police would like to speak with a man known as “DJ,” who was reported to have been with the group.

He is white, about 5 feet, 9 inches tall and 160 pounds. He has a skinny face with acne scars. He is believed to be in his mid- to late 20s. The morning of the slaying he was wearing blue jeans and a gray T-shirt. He also was wearing a baseball cap with a the letter D on it.

Anyone with information regarding the identity of DJ is asked to call the police tip line at 425-257-8450.