Former child star Evan Ellingson's death is being investigated as a possible overdose ... we're told evidence was found at the scene which might point to drug use.
Law enforcement sources tell TMZ ... drug paraphernalia was found at the San Bernardino County home, where Evan was found dead on Sunday. Right now, cops are continuing to investigate and we're told the case is being looked at as a possible OD.
Sources close to the case tell us the pending results of Ellingson's toxicology report will determine how the investigation will proceed -- if drugs are found to have been the cause, authorities could potentially investigate where they came from, and if there's any criminal culpability.
TMZ broke the story, Ellingson's body was found in his bedroom ... and officials told us there appeared to be no foul play involved.
His father, Michael, told us his son was found at a sober living home ... while Ellingson struggled with drugs in the past, Michael says he was doing better as of late.