An investigation is ongoing into the unexpected death of a Colorado man and the poisoning of two others, which could have resulted from MDMA laced with fentanyl, according to a family member of the man who died.

Test restults are not complete. But on the weekend of December 1, three young people out at a nightclub called Beta took what they were told was pure MDMA, which they got from an acquaintance, according to the family member. 

After taking the drug — and no other drugs except alcohol — they showed signs of opioid overdose. The man died at the club, the family member said. The other two ended up in Denver's county hospital. One of the two people who survived tested positive for fentanyl in their system, according to the family member. 

An autopsy has been done but the report won't be completed for weeks, the Denver coroner's office told Rooster. 

Facebook messages sent to the two people who were poisoned but survived were not immediately returned Thursday. 

Fentanyl, a synthetic opioid 50 to 100 times stronger than heroin, is legally used in hospitals and ambulances as a painkiller. On the street, fentanyl is often added to heroin to boost its potency. This kills people.

But in recent months fentanyl has been linked to scores of accidental deaths involving other drugs, such as cocaine and meth, not typically lethal.

If confirmed, this Denver death would be the first time a drug sold as MDMA killed someone because it had fentanyl in it, said drug experts from DanceSafe and Bunk Police, harm reduction organizations that track these things.

Rooster is not printing names until we can better confirm the details, and to respect the wishes of the family.  

The story sent shivers through the community of people who use MDMA, a club drug also known as ecstasy or molly. MDMA creates feelings of warmth and trust, and is finding new life as an aid to therapy. Mitchell Gomez, head of the harm reduction organization DanceSafe, put out warnings on Facebook and Twitter, asking folks to test their drugs.

Gomez said the case was important because MDMA has historically been one of the safest recreational drugs — far safer than alcohol. It's statistically more physically dangerous to drive to someone's house to buy the MDMA than it is to take it. 

"You really have to work to hurt yourself on MDMA," Gomez said. If someone died from unknowingly MDMA laced with fentanyl, Gomez said, that would be "frightening … horrifying."

"I've been in the rave scene since I was 14," Gomez said, "I think I've seen a total of like five or six incidents where someone had a physical problem with MDMA — and certainly nobody's died. And I've been around maybe hundreds of thousands of people who've taken MDMA."

Fentanyl, a downer that leaves you groggy, has very different effects from drugs like cocaine, meth and MDMA, which make you active. So it's unclear why these drugs are mixing. It could be the simple fact that fentanyl feels good, and people like to feel good. Or it could be accidental.

"More than likely than not, it was somebody mixing up two baggies," said Adam Auctor, head of Bunk Police, a drug testing organization. "Let's say that did happen, it's still a good reason for people for people to test MDMA, or anything else, for fentanyl."