According to this story in the Boston Globe, a federal grand jury is investigating municipal marijuana agreements in several municipalities, including Newton. 

At least five communities — Eastham, Leicester, Newton, Northampton, and Uxbridge — confirmed Monday that they have received subpoenas from Lelling’s office seeking information about so-called host community agreements.

The controversial contracts, which each recreational marijuana firm must sign with the community in which it hopes to operate before applying for a state license, typically call for substantial payments to the municipality. Critics have long charged that local officials frequently demand more money than allowed under state law, and that the state’s system of strong local control over cannabis companies is ripe for corruption.