The trial of a Lynnwood man accused of beating his ex-wife, dousing her with gasoline then setting his house on fire with her inside came to an end Monday as the judge declared a mistrial.

The testimony in question came from fire investigator Mikael Makela. He told the jury that in his professional opinion, the Nov. 16, 2014 fire at David Morgan’s house was intentionally set. He further testified he had spoken to Snohomish County deputy prosecutor Paul Stern about this opinion over four conversations.

Defense attorney Donald Wackerman said his office was not informed that the witness would testify to a professional opinion of the house being intentionally set on fire. The information he had been given was that he would confirm previous testimony given by deputy fire marshal Ed Hardesty – that the cause of the fire could not be determined, but an intentionally set fire could not be ruled out.

Wackerman went on to say the prosecution knew of his professional opinion but didn’t share it with the defense.

“The state knew what question it was asking,” Wackerman said. “The state knew what the answer would be or it wouldn’t have asked.”

Stern initially asked if he could look for proof that his office communicated the intention to the defense.

After a 20-minute recess, Stern told the judge the testimony may have gone too far and asked for the opportunity to question Makela again, this time ending on an undetermined cause of the fire rather than an opinion that the fire had been intentionally set.

Judge Joseph Wilson agreed with the defense.

“Since the state went to see if they gave that opinion to (the defense), I have to conclude they knew that opinion would be given,” Wilson said, referring to Stern’s just-completed search for proof.

He said failure to disclose the opinion is a violation of discovery order, which is a violation of the defendant’s rights.

“I do not believe this bell can be unrung,” Wilson said. “Given the state of the house, it’s incredibly prejudicial. I am declaring a mistrial in this matter.”

A hearing has been set for March 10. During that hearing, the defense will ask for the case to be dismissed, which means Morgan could walk away.

Morgan’s ex-wife Brenda Welch was found beaten in a pool of blood inside Morgan’s burning house on Nov. 16, 2014. Several firefighters testified that she smelled like gasoline. She had suffered burns to 20 percent of her body, including her chest, neck and back.

Morgan was the only other person at the house at the time. He was taken to Swedish Edmonds where he was treated for smoke inhalation.

In December 2014, prosecutors charged Morgan with the attempted murder of Welch to avoid paying her more than $50,000 in child support and other payments – and also accused him of setting his own house on fire to cover it up.

Morgan pleaded not guilty to all charges.

–By Natalie Covate