MECHANICVILLE, N.Y. — Toxicology reports have confirmed that diphenhydramine, an over-the-counter antihistamine, was found at fatal or lethal levels in all six people who died in the Harris Avenue tragedy, Mechanicville Police said.

Police said mitragynine, the main active compound in kratom, was also found in four of the six people, according to Mechanicville Police.

Toxicology screenings performed on the six family members found dead in Mechanicville in June are consistent with the findings of the police investigation, according to police. Official findings were released on September 11th.

MORE: Six Lives, One Mystery: The Mechanicville Tragedy

Two adult women, Amy Steadman and her daughter Sarah Myers, as well as Myers’ children, Harper Harmon, 13, Hudson Harmon, 11, and twins Gavin and Gracelynn Harmon, 10, were found deceased in Steadman’s apartment on June 23.

Evidence suggests that all of the children were willfully poisoned, and that Gavin was also fatally stabbed. It is believed they died on June 10, nearly two weeks before the bodies were discovered.