Waikato's Mayor says gangs don't usually cause trouble in the region

They're suspected to be involved in three targeted killings in the last month.

Sixty police are working on the investigations and believe they're all linked.

The district's mayor, Allan Sanson, says gang activity usually flies under the radar, and the region's just a victim of an occasional flare up in tensions.

He says it could have happened anywhere, and is driven by crime and meth.