Opening statements began Tuesday in the second-degree murder trial of Michael Haim, accused of murdering his wife Bonnie Haim back in 1993.

Michael Haim has pleaded not guilty to the charges against him.

On Tuesday, several witnesses were called but the most anticipated witness was that of the son, Aaron Haim, now known as Aaron Fraser.

MORE: The disappearance of Bonnie Haim: Missing in 1993 and unearthed by son in 2014, her husband’s trial begins Monday)

The prosecution didn't ask him about what happened in 1993 but rather focused on how Aaron found his mother’s remains.

Aaron recanted that years after Bonnie Haim's disappearance, on the weekend of Dec. 14, 2014, he rented an excavator and he and his brother-in-law were working on the Haim home when they broke up a brick and concrete slab with a shovel.

He described the gut-wrenching moment on the stand when he made the realization they were remains.

"I picked up the coconut object and it ended up being the top part of her skull…we looked back in the hole and saw teeth."

MORE: HAIM TRIAL: The trial for the man accused of burying his wife in their backyard began Tuesday

The admissibility of that childhood testimony has been challenged by Haim's defense lawyer Tom Fallis. Also challenged: the testimony of Haim at the 2005 wrongful death case brought by his estranged son. Adopted by friends, his son -- now Aaron Fraser -- filed suit and won $26 million, including the family home.

The trial continues Wednesday starting at 9 a.m. The entire case will be live-streamed at firstcoastnews.com.