The Maryland medical examiner's office said it could not determine the cause of a 5-month-old boy's death at a Citicorp daycare near Hagerstown in June.
The agency said Friday it was a case of sudden, unexplained infant death, like those of 2,000 to 3,000 U.S. children under 1 year of age annually.
The boy was in the care of contractor Bright Horizons at Citicorp's credit services complex when ambulance workers responding to a 911 call found him not breathing and in cardiac arrest on June 17.
The Washington County Sheriff's Department hasn't released the child's name. Maj.Sam Billotti says investigators expect to close the investigation soon.