Yale Professor Antonio C. Lasaga was jailed again last Friday after prosecutors alleged he violated the terms of his federal bail bond.

Until his arrest last week, Lasaga had been in home confinement while awaiting trial on federal and state charges, including sexual assault and possession of child pornography. He has pled not guilty to all federal and state charges.

On Friday, the government filed a successful motion to have Lasaga's bond revoked, claiming that he had obstructed justice and violated state law and the conditions of his bail bond by "surreptitiously" accessing computer files belonging to a potential witness in the federal case, according to Kari A. Dooley, senior litigation counsel for the US Attorney's Office. She said Lasaga did so through the Yale computer system.

According to Dooley, federal agents originally arrested Lasaga on November 18, 1998. He was subsequently charged with possession and receipt of child pornography.

He was arrested again on December 9, 1998 and placed under home confinement after he allegedly came into contact with a minor who was a potential witness. He was permitted to leave his home under limited circumstances, Dooley said.

Then, on December 21, the New Haven Police department arrested Lasaga again. State prosecutors charged him with two counts of sexual assault in the first degree, two counts of risk of injury to a minor and two counts of promoting a minor in an obscene performance, according to Senior State Attorney David Strollo. He was released on $250,000 bail.

Strollo said the state has not taken any new action against Lasaga as a result of the most recent incident, but said his office was currently investigating the matter.

"He has not yet been charged with anything as a result of this latest incident by the state of Connecticut," Strollo said.

Lasaga could not be reached and his attorney, William F. Dow III, declined to comment on the case.

"I prefer to try my cases in court, not in the press," he said.

The director of Information Technology Services at Yale University also declined to comment because a federal investigation is currently in progress.

Lasaga was master of Saybrook College at Yale until he resigned on November 6, 1998. He is also a professor of geology and geophysics at Yale.

Lasaga earned his Ph.D. in chemical physics from Harvard in 1976. He also served as a lecturer in Harvard's department of Chemistry and Geology from 1976 to 1977.