BOULDER, Colo. -- The Boulder County burglar who was beaten and stabbed to death by owners of the home he broke into had significant amounts of cocaine, heroin and the prescription antidepressant Wellbutrin in his system, according to coroner.

Evans W. Sussman, 41, died in the Oct. 3 incident in rural Boulder County. The results of a forensic blood screen were released Tuesday afternoon. Cocaine is a stimulant and heroin is a depressant.

"Drawing conclusions from the levels and how it may have influenced (Sussman's) behavior in this situation is difficult because of the individual factors such as drug tolerance," Boulder County Coroner Thomas Faure said in a statement.

The Longmont Daily Times-Call reported Tuesday that investigators seized financial documents, pills and pieces of tin foil containing white powder from Sussman’s home when they searched it two weeks ago, according to a search warrant. They would not tell the paper what the white powder was.

The newspaper also reported that investigators continued to interview a friend of Sussman, identified as Paul Peter Koro, 35. The newspaper said investigators call Koro "person of interest" in the case. Investigators told the newspaper that they are still not clear about whether Koro lived at Sussman’s house, although some neighbors told the newspaper that he did.

The Oct. 3 incident began when a man tried to force his way into the home of a couple on Poorman Road, just off Sunshine Canyon Road, after the woman answered the front door.

The woman said she picked up a metal baseball bat and yelled for her husband's help. The woman told investigators that she tried to push the man outside the front door with the bat, but he wouldn't budge.

The woman's husband wrestled with the man, and was pepper sprayed by the intruder. The husband was eventually able to take away the man's knife and stabbed him with it, investigators said.

Investigators identified Sussman through dental records several weeks after the incident. They said Sussman had arrived at the couple's home by bicycle, and had armed himself with a toy water gun, the knife and pepper spray. He also had with him a green satchel containing small sections of rope, duct tape and zip ties, according to the sheriff's department.

Inside the satchel was a sheath for a hunting-style knife, which was consistent in size with the knife that had been used to attack the couple, according to investigators.

Authorities said the couple were defending themselves under the "Make My Day" law and were not charged in the Sussman's death.

They at first denied knowing Sussman but later said he did work for them several years ago.

Sussman operated a business called Neon Sign & Lighting out of his home.