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A federal judge has loosened the legal leash on "Girls Gone Wild" founder Joe Francis, but kept it taut enough to prevent the soft porn filmmaker from attending an adult industry conference this weekend in Phoenix.

U.S. Magistrate Robert McQuaid denied a motion by Francis' lawyers seeking permission for him to attend the Phoenix Forum, a conference geared toward adult entertainment businesses.

"Girls Gone Wild" is a co-sponsor of the event that runs Thursday through Saturday.

"It doesn't appear to the court that the trip has a valid business purpose," McQuaid said.

Francis, who turns 35 on Tuesday, has been restricted to traveling between Southern California and Reno since March 10, when after nearly a year in jail, he was freed on bail here pending his trial on federal tax fraud charges.

In his ruling issued Monday, however, McQuaid extended Francis' travel sphere to include San Francisco, so he can confer with his tax attorneys.

A federal grand jury in Reno indicted Francis and his companies, Mantra Films Inc. and Sands Media Inc., last April.

The government alleges the companies claimed more than $20 million in phony deductions in 2002 and 2003, and that Francis used offshore accounts to conceal income. His trial is set for August.

Defense lawyers are asking to move the trial from Reno to Los Angeles.

They argue that while an Incline Village address appears on some of Francis' bank statements, the tax returns in question were prepared and likely signed in Southern California.

Additionally, the lawyers said in a motion that the activities associated with the returns occurred in California, and "virtually all of the individuals" who may be called as witnesses reside there.

Government attorneys opposed the change of venue. In court documents, they said Francis "held himself out" to be a Nevada resident, and that Sands Media is incorporated in Nevada. They also charge that a Sands Media bank account at Wells Fargo Bank in Incline Village "was a significant tool in the defendant's tax evasion scheme."

Francis has built a multimillion dollar empire with his "Girls Gone Wild" videos that show young women exposing themselves, often at events like Mardi Gras and spring break.

His endeavors have generated numerous legal battles.

Earlier this month, he settled five-year-old criminal charges in Panama City, Fla., by pleading no contest to child abuse and prostitution charges involving the filming of underage girls in 2003.

On Tuesday, Francis accused U.S. District Judge Richard Smoak in Florida of being behind a new civil lawsuit that accuses Francis of filming underage girls in sexually provocative acts.

Francis said Smoak and Smoak's former law partner, Ross McCloy, are targeting him because his company met with a consulting firm about taking steps to impeach Smoak and have him removed from office.

Smoak presided over an earlier, similar lawsuit against Francis filed by McCloy on behalf of seven women. Francis said the judge should have removed himself because of his relationship with McCloy. The lawsuit was later settled after Smoak jailed Francis for making threats during a deposition.

McCloy also is representing the four women who sued Francis last week. They allege they were 17, 16, 15 and 13 when his company solicited them to participate in sexually provocative videos, and are seeking unspecified monetary damages.