LAKEWOOD, Colo. -- What was initially investigated as a deadly home invasion has turned into a first-degree murder case, Lakewood police said Friday.

Police were called to home in the 1300 block of South Wadsworth Boulevard at about 6:30 p.m. Thursday on the report that a homeowner had shot and killed an alleged intruder.

Floyd Raymond Nuss, 61, said he shot at a man who kicked in his door while trying to break into his house.

But during the police investigation, detectives learned that the alleged intruder was actually Nuss' roommate and had rented a room from Nuss for the past three to four years.

Richard Kohler, 51, was pronounced dead at the scene. His body was found just inside the front door, Lakewood police said.

Detectives arrested Nuss and booked him into the Jefferson County Jail for investigation of first-degree murder.

"We take what he said, what the evidence looks like, all of the things into totality and then make some decisions based on that. We also obviously consulted with the Jefferson County District Attorney's Office," said Lakewood Police Cmdr Michelle Tovrea.

Colorado's "make my day" law states that citizens have the right to expect absolute safety in their homes and are justified in using deadly force against an uninvited person who might commit a crime in the home.

"He's not a troublemaker or anything, so I can't see why he would have problems with anybody who wants to come to his door," said neighbor Joe Vigil.

But police said they don't believe that the law applies in this case, which at first appeared to be an act of self-defense.

Residents in the area said that they are sad that such a violent crime happened in their neighborhood and that one of their long-time neighbors is behind bars, but they are relieved to know that the shooting was not a result of a random break-in attempt.

There were no witnesses at the scene when police arrived so detectives are interviewing friends and acquaintances to see if they can piece together the events leading up to the incident.