DEDHAM, Mass. -- The attorney for Dirk Greineder, a once-prominent Wellesley doctor convicted in the 1999 murder of his wife, argued Friday that his client should be granted a new trial.

NewsCenter 5's Pam Cross reported that Dirk Greineder's attorney said that experiments with the evidence by the jury tainted their decision.

It's been nearly five years since Dirk Greineder was convicted of murdering his wife, Mabel. His attorneys contend that jurors improperly handled evidence, using it for their own tests.

"I don't think it became that relevant," one juror testified.

Two jurors said that during deliberations, they used a piece of fruit -- a banana -- to make an impression with a pair of work gloves. Gloves found near the body were key at the trial.

Mable Greineder was killed while walking near Morse Pond. A witness spotted her husband leaving the woods. Now, the trial judge must decide if jurors acted improperly.

"I remember the banana. What I saw was someone taking the glove and pushing it on the outer skin of a banana," another juror said.

Both jurors testified the impression was compared to stains on a jacket worn by Dirk Greineder. Judge Paul Chernoff asked many questions, but did not voice an opinion.

"We can make a lot of jokes about bananas, but the reality is that the jury was performing their own junk science," defense attorney James Sultan said.

"This is really hopeful, not because I am trying to point fingers at people who tried to do the right thing. I know for a fact that my father is innocent," Dirk Greineder's daughter, Britt Greineder, said.

The defense believes that the jury's independent action behind closed doors was crucial. Prosecutors will likely argue otherwise.