PHILADELPHIA (CBS/AP) — Police in Philadelphia are investigating after nine people suffered fatal heroin overdoses in the city and several other users of the drug were hospitalized in addition.

Several victims died within blocks of one another on Sunday in Kensington, a section of the city that has become synonymous with drug abuse.

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Police have been investigating a bad batch of heroin that’s been circulating throughout the city for the past month or so. A specific brand has yet to be identified.

A bad batch has been blamed for nearly 50 overdose deaths last month within the police department’s East Division, which encompasses Kensington and parts of north Philadelphia.

Philadelphia Mayor Jim Kenney released a statement regarding the overdoses on Monday:

“It is with great sadness that I acknowledge these deaths are just one sign of a larger crisis happening across the nation. Here in Philadelphia, it is almost certain that we will see a significant increase in unintentional drug-related deaths for 2016. These losses are truly heart breaking, and my thoughts and prayers are with the victims and their families.
“The City of Philadelphia is working diligently to address this crisis. In the last year, the Department of Behavioral Health and Intellectual disAbility Services has strengthened their efforts in Kensington, the epicenter of the city’s opioid use, increasing the distribution of NARCAN and providing onsite addiction services. Thanks to this increased presence, 350 individuals have gained access to medically assisted treatment services. Given the complex underlying causes of this crisis, the City also recently created the Opioid Task Force that will begin semimonthly meetings in January and develop a strategy to reduce opioid dependence within 90 days of their first meeting.”

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Police say a cluster of overdoses can occur when heroin is cut with toxic chemicals like fentanyl or rat poison.

On Monday, police announced that the number has risen from six to nine people.

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