PROVIDENCE, R.I. (AP) – In the weeks after a deadly 2003 nightclub fire, Kristina Link testified before a grand jury and offered what prosecutors say was “unparalleled insight” into the inner workings of the concert venue.

But that was before Link’s marriage to Michael Derderian, an owner of The Station nightclub who is scheduled to stand trial starting Sept. 5 for a fire that killed 100 people and injured more than 200 others.

Now, Link is looking to avoid testifying in her husband’s trial on 200 counts of involuntary manslaughter by asserting a marital privilege that legal experts say should succeed in keeping her off the witness stand and make her earlier testimony to the grand jury inadmissible.

A defendant marrying a prosecution witness while awaiting trial adds an unusual twist to an already complex criminal case. Husbands and wives of criminal defendants cannot be compelled to testify at their spouse’s trial if they do not want to – assuming the marriage is valid.

The spousal privilege, intended to preserve the sanctity of marriage, would apply even if the couple was not married at the time of the alleged crime, according to lawyers not connected to the case.

“If they’re married at the time the testimony is proffered, that’s all that counts,” said Robert G. Flanders Jr., a Rhode Island state Supreme Court justice and a nominee for a seat on the 1st U.S. Circuit Court of Appeals.

The Feb. 20, 2003 fire at the West Warwick club began when sparks from a rock band’s pyrotechnics ignited flammable foam used as soundproofing around the stage. Daniel Biechele, former tour manager for the band Great White, is serving a four year prison term after pleading guilty to lighting the pyrotechnics without the required permit.

Jeffrey Derderian, who also owned the club, faces the same charges as his brother, but no trial date has been set for him. It’s not clear if Link will be called as a witness at Jeffrey Derderian’s trial, but if asked to testify, she would not be able to invoke marital privilege to avoid taking the stand.

Link was the office manager for Derco LLC, the brothers’ corporation that owned the club. She testified before the grand jury on three occasions in March 2003, prosecutors say, and gave testimony that the state considers useful to its case. Link and Derderian were romantically involved at the time and married on July 15, 2005, in Narragansett.

“Ms. Link provided unparalleled insight into the day-to-day decision making process, the chain of command and financial condition of the club,” the prosecutors wrote.

Prosecutors consider the Derderians’ finances important because they want to prove the brothers had enough money to renovate their club and make it safer.

The state had subpoenaed Link as a witness at Michael Derderian’s trial. But her lawyer, William Dimitri, told prosecutors in May that she would not testify at the trial because of her marital privilege. Dimitri refused to comment Friday.

Prosecutors filed court papers on June 29 asking for an evidentiary hearing to establish that Derderian and Link have a valid marriage and that Link is definitively unavailable to testify. Although Dimiti has said Link plans to invoke the privilege, it needs to be established on the record and in court, said Michael Healey, a spokesman for the attorney general’s office.

Even without Link, hundreds of witnesses could be called in Michael Derderian’s trial, which is likely to last months.

A Rhode Island statute says spouses of defendants who volunteer to testify cannot be barred from doing so, but Link has already chosen to claim marital privilege.

“I think the argument is going to be, she’s not offering herself and, consequently, if she doesn’t want to testify, she shouldn’t have to testify,” said John Tarantino, a well-known Providence trial attorney.

Legal experts say they don’t expect prosecutors to be able use Link’s grand jury testimony at the trial if Link herself does not take the stand. Grand jury testimony can typically be used only to impeach a witness’s credibility at trial, and defendants – who are absent during the grand jury process – have a constitutional right to cross-examine witnesses.

But Healey, the spokesman for the attorney general’s office, said prosecutors were “looking into the legal parameters that govern the admissibility of prior sworn testimony.”

David Frank, a news reporter for Rhode Island Lawyers Weekly and a former state prosecutor in Massachusetts, said that while “creative lawyers can always try to come up with a creative argument,” it seemed that prosecutors were in a “helpless position” in getting Link to testify.