Authorities in northern California say they have arrested a 29-year-old man who they found unconscious in a home Saturday afternoon with a 13-month-old baby at his side.

Police responded to a home in Santa Rosa – about 60 miles north of San Francisco – around 12:50 p.m. on Saturday. They found a man they identified as Patrick Oneill and an infant lying next to him on the floor of a bedroom. The baby was pronounced dead at the scene.

Police said there were no signs of "physical violence" but they found "signs of recent drug use next to where the child was discovered." It was unclear what role, if any, drugs played in the baby’s death.

Oneill was taken to a hospital with “life-threatening injuries,” police said. He is expected to be booked into the Sonoma County Jail on a charge of suspicion of murder after his release from the hospital, they said.

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“We still have some more investigating to do,” Santa Rosa pole Lt. Dan Marincik told Bay City News. “We saw no signs of physical injury, and there was narcotic paraphernalia in the room. We believe that the 29-year-old put the child in a situation that ultimately caused his death.”

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Anyone with information is encouraged to call the Santa Rosa Department’s Violent Crimes Investigation Team at (707) 543-3590.