Joe Miller, the tea party-backed conservative activist and attorney who defeated Sen. Lisa Murkowski (R-Alaska) in the 2010 primary only to lose to her write-in campaign in the general election, filed a statement of candidacy document to run for the Senate earlier this month, campaign finance records show.

A statement of candidacy form must be filed when a individual raises or spends more than $5,000 or another person does so on behalf of the candidate, according to Federal Election Commission instructions.

Miller had previously announced he was forming an exploratory committee for a run against Sen. Mark Begich (D), so the move is not a total surprise. A telephone call to Miller's office seeking comment was not returned late Tuesday.

Politico first reported the filing.

A Miller bid could complicate Republican hopes of winning Begich’s seat. The conservative candidate made a series of missteps that proved costly in the 2010 race. Lt. Gov. Mead Treadwell (R), viewed as a more electable candidate, has also formed an exploratory committee.