MILAN — Italian police have arrested six men on manslaughter charges for allegedly using pepper spray to carry out thefts at a concert for teens, triggering a stampede that killed six people last year.

Authorities announced the arrests Saturday, nearly eight months after a rap concert for teens near Adriatic coastal city of Ancona ended in tragedy on Dec. 8. The six, all men ages 19-22, were part of a gang based in the northern city of Modena that hit nightclubs in northern and central Italy with the aim of robbing unsuspecting club-goers.

They are under investigation for manslaughter and for causing injury to 197 others.

Survivors said panic spread after the pepper spray was unleashed. The victims were five teens, ages 14-16, and a 39-year-old mother who had accompanied her daughter.