Facebook Inc. suspended another company that harvested data from its site and said it was investigating whether the analytics firm’s contracts with the U.S. government and a Russian nonprofit tied to the Kremlin violate the platform’s policies.

Crimson Hexagon, based in Boston, has had contracts in recent years to analyze public Facebook data for those and other clients, according to people familiar with the matter and federal procurement data. Crimson Hexagon says it has the largest repository of public social media posts,...