Five people had to be revived after suffering a fentanyl overdose in the parking lot of The Shops at Riverside mall in Hackensack, according to city officials.

Police were called to the mall Wednesday afternoon for reports of multiple unconscious people. Officials say that five female mall employees between the ages of 29 and 41 overdosed on the drug.

Officials say that Narcan was administered to all of the women and that four of the five were taken to the hospital. One of the women refused to be taken to the hospital, officials say.

“It is truly heartbreaking to see the terrible toll taken by these illicit and dangerous substances,” Hackensack Mayor John Labrosse wrote in a statement.

Hackensack Police Captain Michael Antista said that the department is investigating the matter to find the source of the drugs.

“[We] will do everything within our power to prosecute those responsible to the fullest extent of the law,” he wrote.