BOSTON

The son of a millionaire business guru accused of staging his own shooting during a family dispute testified Tuesday that his father had threatened to "ruin" him.

John J. Donovan Sr., a former MIT professor, is on trial on charges he faked a shooting in 2005 to gain the upper hand in a battle over family trust funds that could be worth hundreds of millions of dollars. Prosecutors said he then falsely accused his oldest son, James, of hiring would-be killers.

He is charged with filing a false police report, a misdemeanor that carries a maximum one-year sentence.

James Donovan testified Tuesday that his father called him a "demon," said he should be careful because he had young children and a lot to lose. The father warned: "I will ruin you," James Donovan said.

The younger Donovan also told the court that because of the dispute, he moved his family from his house in Hamilton, less than a mile from his father's second home, to another state.

John Donovan, 65, adamantly denies any role in his shooting and insists he was attacked by two strangers on the night of Dec. 16, 2005. But prosecutors say Donovan made up the story to exact revenge.

Donovan was wounded in the abdomen and said he was saved from more serious injury by a large belt buckle. But the emergency room doctor who treated him said he did not see the type of injuries he would expect if the belt were on when the shots were fired.

Donovan, a business professor at the Massachusetts Institute of Technology from 1969 to 1997, made a name for himself as a technology guru. He commanded big fees as a sought-after speaker to Fortune 500 companies, started more than a dozen companies and published 11 books.

He has been involved in legal battles over trusts with James Donovan, his oldest child, and his four other children since 2003. In 2002, one of Donovan's daughters told her siblings that Donovan had sexually abused her when she was a child. Donovan denies the allegation, and has said the claim is a strategy to gain leverage in the dispute.