SAN ANTONIO -- Tuesday a mistress was called a liar in court where a woman is on trial for killing her husband.

Frances Hall is accused of using her car to hit and kill her husband, multimillionaire Bill Hall Jr., nearly three years ago.

She said it was an accident.

Last week, Bonnie Contreras, the mistress of Bill Hall, Jr. testified she was rear ended multiple times during the road rage chase which caused her to veer into oncoming traffic.

Tuesday morning, an expert said that's just not true.

October 10, 2013, Frances Hall was driving her Cadillac Escalade down 1604 near Macdona-Lacoste right behind Contreras in her Range Rover in what's being called a road rage chase.

Bill Hall followed behind on his Harley Davidson motorcycle.

During the high speed chase, Bill Hall tangled up with the Escalade and was ejected from his motorcycle. He later died from his injuries.

Contreras told the court she was rear-ended 15 times by the Escalade, giving her whiplash and causing her to veer into oncoming traffic. She also stated her purse flew onto the floor of the front seat.

Charles Ruble, an accident reconstructionist, debunked that claim.

Ruble recreated the crash for the courtroom showing his version of how Bill Hall was ejected from his motorcycle in southwest Bexar County.

"No. Impact with cycle, no. Impact from the rear 15 times, no. Impact hard enough to get shoved into the oncoming lane, purse going in the floor, no," said Ruble addressing Contreras's claims.

Ruble's finding contradicts the prosecutor’s expert's opinion. Tim Lovett, a collision reconstruction expert, said there was in fact evidence of multiple hits to the back of the Range Rover.

Jose Seguin, Frances Hall's youngest brother, also took the stand Tuesday morning.

He said three weeks before the deadly crash, Frances told him about Bill's affair with Contreras. He admitted this wasn't the first time Bill fooled around on his wife.

Seguin said the couple tried to have alone time after Frances found out about the affair, but told the court that was nearly impossible.

"I know they had gone to Corpus to get away from the situation and that Bonnie wouldn't leave them alone," Seguin said.

Prosecutors said Bill Hall filed for a divorce earlier in the week of the deadly crash, before moving out.

Seguin also told the court he was told Frances beat up Bill the week of the accident, but didn't follow up with her about the incident.

Frances Hall maintains her innocence saying this was all an accident. She is charged with first degree felony charges of murder and aggravated assault with a deadly weapon. She faces life in prison if convicted.