Four homeless men were killed and another person was injured around Manhattan’s Chinatown neighborhood during attacks that authorities believe took place while the men slept, New York City police said Saturday.

Investigators began making the grisly discoveries around 2 a.m. Saturday morning after receiving a call about an assault in the area. They initially found one man’s body and were approached by an injured 49-year-old man. Police later found three more bodies, and the injured man was taken to a nearby hospital in critical condition.