NEW YORK (CBSNewYork) — The NYPD says they’ve made over a dozen arrests after close to 50 people overdosed on K2 in just a few days. Police say the toxic batch of K2 is making its way around Brooklyn, prompting an urgent warning from NYPD Chief of Department Terence Monahan, who says this strain of the “dangerous, deadly drug” is “especially threatening.” Advisory alert warning people about a particularly toxic batch of K2 that has triggered 49 overdose cases originating at five locations in #Brooklyn . More information here: https://t.co/WUcM0ufUpC pic.twitter.com/eqDnvW9AAg — Chief Terence Monahan (@NYPDChiefofDept) May 22, 2018 Images released by investigators show packages of the synthetic marijuana. Police say they were recovered over the last couple of days after reports of at least 49 overdoses at five locations in Bushwick, Bed-Stuy, East New York and Brownsville since last Friday. (credit: NYPD) “All residents who live near these five locations are warned about exceedingly dangerous K2 batches in circulation, and advised to avoid usage,” Monahan said in a statement. “Residents are urged to call 911 immediately if they or someone they know are showing symptoms of overdoses.” So far, at least 13 people have been arrested but police say they are still working to determine the exact source of the drug’s distribution. While some of the users from the weekend overdoses were treated at local hospitals, others refused medical help. “The sadness of seeing somebody struggling to the point of where they cannot take care of themselves,” said Felix Morelo. The 13 people arrested in connection with the investigation are expected to face a judge sometime Tuesday.