Police are investigating after a 4-month-old infant died while at Sunnyvale daycare Wednesday afternoon. 

The Sunnyvale Department of Public Safety said officers and fire personnel responded to a call of a baby not breathing at a licensed daycare facility at around 3:53 p.m. Despite providing aid after arrival, the 4-month-old died. 

The department did not clarify the cause of death, but it and the Santa Clara County District Attorney’s Office are now investigating.