Eric Foster, who also goes by the last name of Luna, appeared Friday in Kern County court for the first time to face accusations that he beat his live-in girlfriend's child to death.
Court documents say Foster admitted to sheriff's investigators that he physically abused the child on at least three occasions.
Trinity's mother, Angela Vickrey, rushed her to the hospital, but medical staff couldn't revive the girl. Kern County deputies were called when the hospital staff noticed obvious signs of trauma, the sheriff's office said.
Foster is being held in jail without the option of posting bail.