From left, Cullen Marino, 22, has been charged with two counts of criminally negligent homicide. Kyle McNutt, center, and Chase Nunez were found dead at Marino's Grapevine home.
Two high school students who were found dead earlier this month died of mixed-drug toxicity, according to the Tarrant County Medical Examiner's Office.
Kyle McNutt, 17, and Chase Nunez, 18, were found dead in a Grapevine home Jan. 5. Both lived in Grapevine and attended Carroll Senior High School.
The Tarrant County medical examiner has ruled that the McNutt and Nunez both died of a toxic mix of heroin, codeine, alprazolam and diphenhydramine.
Police have said that the teenagers were hanging out with Cullen Marino, 22, the night of Jan. 4. His father called 911 the next morning and told the operator that he "might have two dead kids upstairs in my house."
Investigators said Marino moved them to a different room in his house instead of calling 911 after he discovered during the night that they were unresponsive.
Marino is charged with criminally negligent homicide.
Police discovered narcotics and drug paraphernalia in the home, according to a search affidavit.
The document says officers "observed, in plain view, a clear baggie with powdery residue on the table beside the bed..." The document goes on to describe, in an adjacent room, a spoon believed to contain heroin residue and what appeared to be the makings of a mobile meth lab.
According to the affidavit, pipes and bongs for smoking marijuana, a small bottle of Xanax, white powder, an orange pill, a baggie containing possible marijuana and scales were all removed from the home.