Detroit Police have busted a large illegal marijuana grow operation on the city's east side.
Investigators say they conducted surveillance for a while, before going in the building on Gratiot.
Inside, they discovered more than 200 plants. They arrested one person and recovered one gun.
It was part of Operation Ceasefire, where they are taking neighborhoods back one at a time.
There were four rooms inside the warehouse filled with plants.
Police say they also did undercover buys of drugs at convenience store and gas stations in the 9th Precinct.
Police say they believe this was strictly a grow operation, and the marijuana was sold at other locations by street level dealers.
They say it's all about improving quality of life issues.