TWIN FALLS — First-degree murder charges have been filed against a man accused of shaking a 2-month-old baby and hitting its head against the edge of a crib, court records say.

Logan Danial Penner, 19, was initially charged with felony aggravated battery after the Nov. 25 incident, but the Twin Falls Prosecutor’s Office amended the charge Friday after the baby died.

The baby boy, identified as Peyton Rice, was transported to St. Luke’s Boise Medical Center, where he was taken off life support Wednesday.

The first-degree murder charge, as stipulated by Idaho Code, is a result of Penner perpetuating an aggravated battery on a child under 12 years of age, records show.

Twin Falls County Prosecutor Grant Loebs said Monday that pre-meditation is not alleged in the case against Penner.

An autopsy showed the cause of death to be blunt force trauma to the head, court records say. In addition, signs of a fracture discovered on the baby’s upper arm were also found to have been caused by blunt force trauma.

Court records made available to the public don’t indicate when the arm injury occurred. The initial police report called it a “healing fracture.”

Records say that Penner, who was caring for Peyton while his mother, Penner’s girlfriend, admitted to police that he grew frustrated with the baby constantly crying and shook it, and his head hit the edge of the crib. Penner then put the baby back into the crib and later came back to find the baby unresponsive.

At the time of the incident, the mother was doing laundry at another location, records show.

Penner is being held on a $250,000 bond and a preliminary hearing has been set for Friday.