Police arrested a man in connection with the shooting deaths of his wife, who had dementia, and his sister, who was in a coma at a nursing home, authorities in Los Angeles announced Wednesday.

The suspect, whose name was not released, may have at one time applied for a job at the nursing facility where his sister was being cared for, according to CBS affiliate KCAL.

Lisa Nave, 58, had been in a coma at Country Villa Sheraton Nursing and Rehabilitation Center for five years, local reports stated. The suspect is believed to have entered the 138-bed facility as a visitor and shot Nave in the head with a small-caliber handgun Wednesday morning, police said. The man then allegedly left the building and sat on a patio until he was taken into custody.

When police entered the suspect’s home, they discovered his wife also had been shot and killed. She had been experiencing dementia symptoms due to a degenerative disease, according to NBC affiliate KNBC.

Police described the shootings as possible “mercy killings.”