Police are investigating three deaths in northeast Denver on Sunday evening as possible drug overdoses.

The three individuals were found in the 4500 block of Kittredge Street in Denver’s Gateway neighborhood, police said Sunday on Twitter.

Late Monday morning, Denver police officials added that “preliminary investigation revealed that it is possibly a drug overdose.”

When asked if the deaths were fentanyl-related, a police spokesman said in an email that the cause of death was still under investigation.