The source of the super-heroin, which made 130 people die in the Midwest of US, is under the investigation of federal and local officials in the U.S. Midwest.
The New York Times reported yesterday that nearly all deaths are in and around Chicago and Detroit city and some are also from St. Louis to Philadelphia.
Fentanyl, an additive of heroin is 50 to 100 times more powerful than morphine. Health officials said fentanyl enhances the effect of the heroin and also make the respiratory system to shut down.
Drug Enforcement Administration also finds some overdose cases - Chicago Police Superintendent Philip Cline, says.
Police from the city published fliers warning drug users to avoid using and distributing it.