KANSAS CITY, Mo. (AP) -- U.S. attorneys are pursuing allegations of bribery, conspiracy and mail fraud as part of an investigation into former Missouri House Speaker Rod Jetton, according to court documents received by a former lawmaker summoned before the grand jury Tuesday.

Former Republican Rep. Bob Johnson, of Lee's Summit, said U.S. attorneys quizzed him about whether he knew of a $35,000 political contribution by the adult entertainment industry, and whether that money played a role in Jetton's decision to assign a 2005 bill regulating sexually oriented businesses to a committee Johnson led.

Johnson said he told grand jurors that he was unaware at the time that money had been given to a political fundraising committee with ties to a Jetton adviser. Johnson said he asked to receive the bill, which he opposed as an infringement on civil liberties and local zoning powers. He said Jetton never explained why he assigned the bill.

"I thought it was interesting, because he's a part of the very conservative Republican majority, and they usually want to restrict people's rights in this area" of sexually oriented businesses, Johnson said in a courthouse interview after his testimony Tuesday.

Johnson's subpoena to testify, which he showed The Associated Press, cited three federal laws covering bribery, conspiracy and mail fraud. Johnson, who said he is not a target of the probe, said the grand jury's questions focused on the 2005 legislation and did not delve into other subjects.

Jetton said he plans to testify before the grand jury on Wednesday. He has denied any link between the contribution and his handling of the 2005 bill.

Jetton also is scheduled to be arraigned Wednesday in state court on an assault charge stemming from a sexual encounter with a woman last fall. He has said he is not guilty of that charge.

Johnson was at least the fourth past or current public official to appear before the federal grand jury investigating Jetton.

Last month, Republican state Sen. Matt Bartle, of Lee's Summit, told reporters after his testimony that he believes there was a link between the $35,000 contribution and the demise of his original 2005 bill regulating sexually oriented businesses.

But Johnson said Tuesday: "I think Matt's being paranoid."

Also testifying last month was Jackson County Circuit Judge David Byrn, who in 2005 was an attorney and treasurer of the political fundraising committee that received the adult entertainment money. Byrn declined to tell reporters last month if he knew why the contribution was made, citing the ongoing federal investigation.

Chris Benjamin, who was Jetton's chief of staff from 2005 to 2007, told The Associated Press on Monday that he also testified before the grand jury in February. Benjamin said he was asked about the $35,000 donation and Jetton's decision to send the adult entertainment bill to Johnson's committee.

But "I don't want to get into the investigation part of it, because I probably will get called up as a witness if it goes to trial," said Benjamin, a Harrisonville attorney who ran unsuccessfully for state Senate as a Democrat after leaving Jetton's staff.

The 2005 bill at issue would have enacted a $5 per customer admission fee for strip clubs, adult movie houses and other sexually oriented businesses, along with a 20 percent tax on the revenues. The proceeds would have gone to public schools.

The bill also would have required the businesses to close by midnight and barred people younger than 21, tipping, touching and nudity. Seminude employees would have had to remain on a raised stage at least 10 feet away from customers.

After the bill passed the Senate on March 29, 2005, Jetton assigned it on April 4, 2005, to the House Local Government Committee led by Johnson. Between those dates, a political committee for the adult entertainment industry gave $35,000 to the Committee for Honest Campaigns, a political fundraising committee that helped finance Republican campaigns and employed House General Counsel Don Lograsso -- a Jetton adviser -- as a consultant.

Johnson said Jetton asked him to pass the bill out of the House Local Government Committee a couple weeks after sending Johnson the legislation. The House committee eventually endorsed a revised version that dropped the taxes and fees. But that bill never reached the House floor.

Shortly before the 2005 session ended, Sen. Gary Nodler, R-Joplin, attached a scaled-back version of the adult entertainment provisions to a drunken driving bill sponsored by Jetton. That version -- which included no taxes, fees nor restrictions on tipping and closing hours -- passed and became law.

A court struck down the section on sexually oriented businesses, saying it violated a state constitutional ban on legislators changing a bill's original purpose.