A deadly mix of heroin and the powerful painkiller fentanyl has felled drug users across the country, and officials say the fentanyl may have come from a drug lab in Mexico, the Detroit Free Press reported June 3.

The lab, raided by Mexican police last weekend, produced fentanyl that appeared to match that found in the deadly batch of heroin that has killed users from Chicago to Philadelphia. "We do not have 100-percent confirmation that's the source, but it is one of the solid leads we have," said Carolyn Gibson, spokeswoman for the DEA's Detroit division. "We're extremely hopeful that it may be the source of the deadly mixture."

Gibson said the chemical signature of the drug could be traced just like forensics experts can trace a bullet back to the gun that fired it.

A dozen heroin users died in the Detroit area in just one 24-hour period last month after taking the heroin-fentanyl mix.