You were probably hearing TGID 820, which is the North Metro Drug Task Force's talkgroup. Most of their traffic is encrypted since many of the people they are after have scanners to try and stay a step ahead of them. Their talkgroup is assigned to the Anoka County system, but the NMDTF is a team of specially trained officers from the Anoka and Hennepin Co Sheriff's depts and several area police depts. They investigate and serve search warrants on suspected drug operations in Anoka and northern Hennepin counites.