Colorado Republican Tom Wiens has filed the paperwork to make official his 2010 campaign for the Senate.

Wiens, a former state senator, filed a statement of candidacy and a statement of organization on Oct. 27 with the Senate public records office in Washington, D.C. He had previously formed an “exploratory” committee to consider challenging Democratic Sen. Michael Bennet.

Wiens told The Colorado Statesman newspaper earlier this month that he would make an official announcement of candidacy in the first week of November. He told the publication that he has a 100-person campaign finance team to help him raise the millions he’ll need for the race.