A team of alleged cellphone thieves were busted at Lollapalooza by undercover police work from the Chicago Police Department.

At least ten people were arrested at various points during the weekend of the Grant Park music festival. Chicago police said the suspects were working as a team.

Undercover officers spotted at least one person appearing to steal cellphones. Police then tracked them to another location where the phones were dropped off.

Dozens of phones were recovered, police said.

Most of the suspects who were arrested are from out of state, police said.