PHOENIX – With just one week until Arizona’s primary election, political spending to affect legislative races paid for by outside groups that don’t disclose the source of the money amounts to almost half a million dollars.

The $478,000 in “dark money” was spent in the past six weeks, ramping up during the past two, once early ballots were mailed to Arizona voters.

A Republican-leaning legislative district representing northwestern Arizona, including Kingman and Lake Havasu City, has attracted the most money — about a quarter of the spending so far. “Dark money” groups have spent almost $65,000 to help Rep. Sonny Borrelli, R-Lake Havasu City, defeat former Sen. Ron Gould, R-Lake Havasu City, in the race for their district’s senate seat. “Dark money” groups spent $50,000 in the fight over the district’s two house seats.

Another $84,000 has been spent in Legislative District 12, a Republican district in the suburban, southeastern corner of the Phoenix metro area, including parts of Gilbert and Chandler. All of the “dark money” spent in the district has gone to help one slate. Positive spending has gone to help Rep. Warren Petersen, R-Gilbert, move from one of the district’s two House seats to the Senate, and to help re-elect veteran legislator Rep. Eddie Farnsworth, R-Gilbert, and to help newcomer Travis Grantham, R-Gilbert, replace Petersen. Negative spending has gone to defeat fellow Republican candidate for Senate Jimmy Lindblom, R-Gilbert, and Republican House candidate LaCinda Lewis, R-Gilbert.

American Federation For Children, Inc. spent the most “dark money” in Arizona so far, with $213,000 going mostly to help specific Republicans in primary fights. The group spent $24,000 to help one Democrat, Steven Begay, who is running for the Senate in the heavily Native American Legislative District 7. The pro-charter school group spent only $205,000 during the entire 2014 election cycle.

Arizona Free Enterprise Club spent roughly $77,000 so far, also entirely to sway Republican primaries. The group ended up spending roughly $248,000 in legislative races during the 2014 cycle, and another $1.2 million in statewide races that year.

Be sure to follow AZCIR’s Dark Money Twitter Bot (@AZDarkMoneyBot) for near-real time “Dark Money” updates.

Download all “dark money” transactions

An earlier version of this story inaccurately accounted for Steven Begay as running in the House Republican primary. He is running in the Senate Democratic primary.