So who’s behind all those mysterious attack ads against local Congressman Peter DeFazio?

The answer is a reclusive, conservative Wall Street mega-millionaire who installed a $2.7-million toy train set in his mansion and spent $28-million to buy up adjoining Manhattan apartments for his daughter and would get hit by taxes on large Wall Street speculators proposed by DeFazio, according to reports in the Oregonian, Washington Post and Willamette Week.

Just who was behind “Concerned Taxpayers of America,” the group funding the attack ads, was a secret until Friday when the group was legally required to report its donors. The report listed just two “concerned taxpayers”— a Maryland concrete baron who has bankrolled opposition to a Maryland congressman and $200,000 in contributions from secretive hedge fund manager Robert Mercer, a major contributor to DeFazio’s right-wing opponent Art Robinson.

The ads have helped Robinson—an irascible, fringe chemist who has called for the elimination of public schools, the EPA and social security and claimed global warming is a hoax and radioactive waste has health benefits—pull within six points of DeFazio in a recent Republican poll. The revelation of who funded the ads now comes after many may have already returned their ballots in Oregon’s vote-by-mail election.