A Stearns County father faces a possible life sentence after a grand jury indicted him on charges of first degree murder in the suspected shaking death of his 2-month-old son.

Robert J. Kaiser, 32, initially was charged with second-degree unintentional murder, but an autopsy found evidence of previous injuries including bruising and healing rib fractures that a pediatrician deemed suspicious.

Kaiser has been held at the Stearns County jail since his arrest in lieu of $500,000 bail.

He has his first court appearance Friday at 2:30 p.m.

According to the complaint:

Kaiser was alone with the baby on Aug. 27 at the family's home in Farming Township south of Albany when he texted the baby's mother to complain that the baby was keeping him awake. The mother told investigators that the baby seemed different when she returned home. She and Kaiser took the baby to Albany Area Hospital that evening, where doctors diagnosed a traumatic brain injury.

The baby died from his injuries Sept. 3.

Kaiser first denied knowing anything about the baby's injuries, but then told investigators that he fell while holding him. A pediatrician who reviewed the case told investigators that Kaiser's story didn't explain the baby's injuries. The Ramsey County Medical Examiner ruled the baby's cause of death as traumatic brain injury and suggested that it was caused by shaking.

Kaiser was charged Sept. 5 with second-degree unintentional murder.

Matt McKinney • 612-673-7329