Three people were killed in separate attacks on Memorial Day, as the city marked the traditional beginning of the summer season, according to the Chicago Police Department.

Around 8 a.m. Monday, a 43-year-old man was shot in the 8000 block of South Stewart Avenue on the South Side, police said. He was taken to University of Chicago Medical Center in critical condition and later died.

Earlier, in Douglass Park, a man was shot multiple times around 6 a.m. in the 1400 block of South Sacramento Drive, police said. He was pronounced dead at Mount Sinai Hospital.

A 23-year-old man was fatally stabbed in a second floor apartment in the West Side’s South Austin neighborhood around 1:30 a.m. on Monday. The attack was perpetrated by two males in the 300 block of North Long Avenue, according to police.

No one was in custody in any of the attacks, police said.

At least three other people were shot in Chicago throughout Monday, according to police records.

In all, since Friday, Chicago police have investigated at least 31 shooting incidents over the holiday weekend.