The boxes landed in the office of Montana investigators in March 2011.
Found in a meth house in Colorado, they were somewhat of a mystery, holding files on 23 conservative candidates in state races in Montana. They were filled with candidate surveys and mailers that said they were paid for by campaigns, and fliers and bank records from outside spending groups. One folder was labeled "Montana $ Bomb."
The documents pointed to one outside group pulling the candidates' strings: a social welfare nonprofit called Western Tradition Partnership, or WTP.
Altogether, the records added up to possible illegal "coordination" between the nonprofit and candidates for office in 2008 and 2010, said a Montana investigator and a former Federal Election Commission chairman who reviewed the material. Outside groups are allowed to spend money on political campaigns, but not to coordinate with candidates.
"My opinion, for what it's worth, is that WTP was running a lot of these campaigns," said investigator Julie Steab of the Montana Commissioner of Political Practices, who initially received the boxes from Colorado.
The boxes were examined by Frontline and ProPublica as part of an investigation into the growing influence on elections of dark money groups, tax-exempt organizations that can accept unlimited contributions and do not have to identify their donors. The documents offer a rare glimpse into the world of dark money, showing how Western Tradition Partnership appealed to donors, interacted with candidates and helped shape their election efforts.