Chicago has seen a sudden spike of heroin overdoses over the past three days. The latest reports say that about 74 cases have been reported in 72 hours.

Most of the cases have been reported from Chicago's West Side. Chicago Fire Department spokesman Larry Langford said that the number of cases this year has more than doubled as compared to last year while confirming that there had been 74 overdoses in the past 72 hours, reported NBC Chicago.

Law enforcement officials feel that a batch of heroin may have been laced with the painkiller fentanyl. When fentanyl is added to heroin, it increases the potency of the drug multiple times.

"Add fentanyl to heroin, its potency goes through the roof," said Jack Riley, acting deputy administrator for the U.S. Drug Enforcement Administration, according to DNA Info.

"Hopefully, we'll get this heroin off the streets," Assistant Deputy Fire Commissioner Mary Sheridan said.

Doctors are having a difficult time dealing with patients as the normal treatment for heroin overdose is not working with the latest slew of cases.

"Typically if it's given by the paramedics, we may not need to give it again in the emergency department. But we're noticing we were giving more in the emergency department to these patients," said Dr. Tarlan Hedayati at Stroger Hospital, who is attending to the patients, reported ABC7 Chicago.

The DEA and police are trying to trace the source of the heroin, but they have not been successful until now.