Henry Lehr, 23, of Tucson, Arizona, was shot about 4:15 a.m. Aug. 26 in a home near Indus Street and Redlands Drive.
Lehr had left a residential detox center about 4:10 a.m. that day and told staff he was seeing "demons," according to the Orange County DA's office.
Lehr got into a yard of a home a few doors from the detox center and was pounding on the front door and ringing the bell as he demanded to be let in, prosecutors said.
Lehr eventually broke in and was walking up the stairs when the homeowner woke up, retrieved his pistol and demanded that the intruder stop and identify himself, prosecutors said.
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When Lehr did not respond and kept dashing up the stairs, the man opened fire and then turned to his wife to call 911 for Lehr, who was shot in the chest, prosecutors said. He was pronounced dead at the scene.
"A homeowner has the absolute right to protect themselves from someone who breaks into their home in the middle of the night and threatens their safety," Orange County District Attorney Todd Spitzer said.
"The loss of life is tragic in any situation and this situation is made even more tragic by the fact that an individual who went to a group home to get help with his addiction issues ended up on a deadly collision course with a homeowner who was just sleeping in his own bed in his own house.
"I have fought against allowing group homes in residential neighborhoods my entire career, including as a member of the state legislature, for this very reason," Spitzer said. "People at that group home knew that young man was struggling -- yet no one went to check on him.
"People struggling with addiction issues need to have a safe environment where they can work toward sobriety, and people living in residential neighborhoods should not have to live in fear of waking up to someone struggling with addiction breaking down their front door."