The Maine Republican’s reelection campaign is backed by at least $7.4 million in dark-money contributions that resemble the shell donations that drew FBI scrutiny.
https://www.huffpost.com/entry/susan-collins-faced-an-fbi-investigation-over-dark-money-its-still-flowing-to-her-reelection-campaign_n_6abd5e87e4b02a789b327709