The death of a 4-month-old baby has been ruled a homicide after toxicology tests determined the child had high levels of Benadryl in his system, according to multiple reports.

Adam Seagull, of Shelton, Connecticut, died on March 22 at an unlicensed home day care in Fairfield, The Associated Press reported.

An autopsy determined the infant died of acute diphenhydramine intoxication, according to the wire service. The death was initially ruled accidental and believed to be from Sudden Infant Death Syndrome (SIDS).

No charges have been filed in the case.

Fairfield police told WTIC that investigators are focused on determining whether the child was accidentally given too much of the over-the-counter drug responsible for his death or whether the child was intentionally dosed.

Authorities plan to file charges against the daycare operator for running a daycare out of a private home without a license, according to the TV station.

Diphenhydramine, marketed as Benadryl, is an antihistamine meant to fight allergies. It is also a sedative.