A Seminole County man has been arrested after deputies said he admitted to shaking a 7-month-old baby, who died Saturday in the hospital.

Stephen Rodriguez, 25, of Sanford, was arrested Sunday on charges with first-degree murder and aggravated child abuse for the death of his girlfriend's infant son, Aiden Downs.

Deputies arrived at a Sanford home on Thursday, when Rodriguez, who was caring for the child alone, called 911 to report the child was not breathing.

The baby was immediately transported to Central Florida Regional Hospital in Sanford, and was later transferred to Winnie Palmer Hospital in Orlando, where he died on Saturday.

Deputies said Rodriguez first told them that he dropped the child, which caused the baby to be unresponsive, but he later admitted to shaking the baby.

The suspect claims it was an accident, but Seminole County deputies don't buy it.

The arrest report states that the child's mother, Jazzmine Downs, recorded a phone conversation with Rodriguez where he admitted to shaking the baby for about a minute.  Deputies said that Rodriguez did not know he was being recorded.

Now Rodriguez is in the Seminole County Jail without bond. 

His next court hearing scheduled for June 3 at 1:30 p.m. in front of Judge Lester.