Redflex villain queries absent Aust exec

The central figure in Redflex's $US124 million Chicago scandal has asked a judge to toss out his conviction because the red-light camera company's former high-ranking Australian executive did not testify at last month's trial.

John Bills, 54, the former second-in-command of Chicago's Department of Transportation, was found guilty of 20 counts including bribery, extortion and wire fraud charges on January 26.

Bills pocketed up to $US2 million in bribes and gifts from Redflex and in return helped steer $US124 million in business to the ASX-listed company in a decade-long scheme that made Chicago the red-light camera capital of America.

Bills faces a maximum 304-year jail term when sentenced in May.

"Defendant Bills moves this court to set aside the jury verdict in this case and enter a judgment of acquittal," Bills' lawyer Nishay Sanan wrote in a post-trial motion to US District Court judge Virginia Kendall on Monday.

Mr Sanan pointed to how Bruce Higgins, Redflex's North American chief executive from 2001 to 2005, was not called as a witness at Bills' trial.

He argued prosecutors introduced ample hearsay statements by Mr Higgins by way of other witnesses.

"Higgins was unavailable to testify, and was not subject to cross-examination," Mr Sanan argued.

"Higgins' statements were testimonial in nature, and should not have been admitted without Higgins being subject to cross-examination.

"Allowing Higgins' statements in evidence was in error."

Mr Sanan also pointed to Mr Higgins' absence last month during the trial's closing arguments.

"By the way, where is Bruce Higgins?" Mr Sanan asked the jury, the Chicago-Tribune reported.

Mr Higgins' successor, American businesswoman Karen Finley, was vice president of Redflex's North American operations from 2001 and then took over as chief executive from late 2005 through to February 2013.

Finley entered a guilty plea last year to funnelling bribes to Bills in exchange for red-light camera contracts in Chicago.

Bills' bagman, Martin O'Malley, has also entered a guilty plea over his role.

Finley, O'Malley and Aaron Rosenberg, a top Redflex salesman in the US, were prosecution witnesses at Bills' trial.

Mr Sanan attacked their credibility in his demand for Bills' guilty verdicts to be tossed.

"As was established during both the direct and cross-examinations of Finley and Rosenberg, both are admitted liars and had previously lied under oath," Mr Sanan wrote.

"Although O'Malley had not previously lied under oath, his story was largely unsupported by anything other than his own self-serving statements."

Melbourne-headquartered Redflex is being investigated by the Australian Federal Police over its Chicago dealings, the company announced.

Mr Higgins has not been charged in the matter.