The investigation following a 20-year-old man's fentanyl overdose death led the DEA to arrest his ex-con father who was allegedly leading an illegal hallucinogenic mushroom grow operation in Clairemont.

The overdose victim, who lived with his father, died several weeks ago, according to the DEA. The DEA Narcotics Task Force was under the suspicion he was a drug dealer.

Following his death, agents arrested his father for possession of an illegal weapon, ammo, and drugs which were found in their home on Jemez Street in Clairemont.

Then on Thursday morning, evidence gathered during the Task Force's continued investigation led them to a rental office space on Clairemont Mesa Boulevard where agents discovered a "very large" hallucinogenic mushroom grow operation and and a butane honey oil extraction lab.

Agents suspect the overdose victim'd father to be one of the main growers, according to the DEA. The street value of the illegal mushrooms is estimated in the tens of thousands of dollars.

A HAZMAT crew had to be called in due to the risk of the poisonous mushroom spores in the air, the DEA said. The office space will need to be decontaminated before anyone else rents it.

Hallucinogenic mushrooms, also known as "magic mushrooms" or "shrooms," according to the DEA, can cause psychosis or death.