The prosecution's only witness said Monday she did not have a full-time business relationship with Wichita abortion provider George Tiller.

The denial strikes at the main issue that has Tiller on trial in Sedgwick County District Court, charged with 19 misdemeanors.

Prosecutor Barry Disney indicated that Kristen Neuhaus changed her story from what she told another assistant state attorney general more than two years ago.

Neuhaus said that prosecutor Steve Maxwell -- a deputy to then-Attorney General Phill Kline -- so harshly interrogated her during a secret hearing that she's not sure what she said.

That marked the first day's testimony in the case against Tiller in a trial to decide whether he violated a Kansas law regulating late-term abortions.

The trial is being watched by abortion opponents across the country.

"This is the biggest trial in the history of Kansas," Pat Mahoney of the Christian Defense Coalition, Washington D.C., told some two dozen people in front of the Courthouse on Monday morning.

Tiller is charged with having an improper business relationship with Neuhaus during 19 late-term abortions in 2003. Tiller is charged with 19 misdemeanors, one for each of those abortions.

"I would be asked to evaluate the patients and see if their pregnancy constituted a substantial and irreversible threat to their health," Neuhaus testified.

That wording --"substantial and irreversible" -- is important. By law, two physicians must make that determination before a woman can undergo an abortion in cases where the fetus could survive outside the womb.

Both sides agree that all 19 of the abortions in question were performed after Tiller had determined the fetus was viable and that the pregnancy put the mother's mental or physical health in danger.

Each time, Neuhaus signed off as the second opinion.

Neuhaus testified she began doing such consulting on late-term abortion cases at Tiller's Women's Healthcare Services Clinic in Wichita in 1999.

"Would you agree that right around 2003 that you became a full-time consultant for the defendant?" Disney asked.

"No, I did not," Neuhaus said.

On Dec. 8, 2006, Maxwell asked Neuhaus the same question during an investigation into Kansas abortion clinics.

"This was the years right after he was shot," Neuhaus said in a transcript Disney showed to the jury. "I became a full-time consultant."

"I did use that word," she said Monday.

But she said she misspoke.

"I was the only one doing consultations," she said. "I should have said 'only.' "

Neuhaus said her 2006 testimony came during a contentious hearing as part of what prosecutors term an inquisition. That's an investigation into whether a law has been broken.

"I was being interrogated for four hours," she said. "I was probably distraught. I don't know why I said some of these things."

Neuhaus, who ran a medical practice in the Lawrence area, said she only came to Wichita to do consultations at Tiller's clinic once a week for half a day.

"I wouldn't call that full-time," she said.

To convict Tiller, the state must show that he had an improper legal or financial relationship with Neuhaus.

"This case isn't about abortion," Disney told the jury in his opening statements Monday morning.

It's about their business relationship, he said.

"It's about this defendant intentionally setting up this relationship, so he could continue business as usual," Disney said.

Tiller is one of the few doctors in the world who performs late-term abortions, his lawyer Dan Monnat said in his opening address.

Monnat contends Tiller did not pay Neuhaus or control her medical opinions. Although she visited with patients at the Wichita clinic, she sometimes did not sign off on Tiller's original diagnosis, Monnat said.

"The evidence will show that the prosecution's theory makes no legal, medical or common sense," Monnat said.

The jury may not get to consider Monnat's theory for the defense, however.

Sedgwick County District Judge Clark Owens took under advisement how he would rule on Monnat's defense that Tiller was acting on advice from his lawyer at the time and the Kansas Board of Healing Arts.

Monnat said the state's medical licensing board recommended Tiller use Neuhaus for his second opinions in 1999. Tiller's then-lawyer, Wichita attorney Rachael Pirner, agreed.

Neuhaus had been working as an abortion provider in the Lawrence and Kansas City areas since the mid-1990s.

Monnat said the state can't prosecute someone for a crime for following its recommendation.

Owens said the law allows advice of counsel or "ignorance of the law" to be used as a defense in a limited number of cases.