An autopsy released Monday states a Clairemont man waited two weeks before burying his mother in the backyard, after she died 15 years ago.

The son appeared in court Monday charged with cashing in on his mother's retirement checks to the tune of $300,000.

It was a not guilty plea in court Monday from 65-year-old Rand Washburn. He is facing two felony counts of grand theft for allegedly stealing more than $300,000 from his dead mother's state and federal retirement accounts.

"This is a large amount of money. Two victims. Two government entities. It was a pattern of fraud that took place over the past 15 years," said Deputy District Attorney Kate Cutsinger.

A newly released autopsy report states Emily Fox died in the bathroom of her home on Tamres Drive during the early 1990's.

The repot says Washburn placed his mother's body in her bed and left it there for two weeks before finally burying her in the backyard.

In January, police found Fox's skeletal remains wrapped in a mattress pad, bed sheets and secured with duct tape, according to the report.

Washburn's defense attorney admits that his client continued cashing Fox's retirement checks after she died.

"There were checks being deposited into a joint account. It was difficult for him to face up to what he was doing, and what he had done," explained Defense Attorney Knut Johnson.

Washburn claims his mother died of natural causes though the medical examiner has been unable to determine the cause of death. And, nobody is saying exactly how she died at the approximate age of 73.

"I'm not a physician and neither is Mr. Washburn. Other that she was elderly and not in very good health at all," continued Johnson.

Emily Fox worked for decades as a secretary at Marston Middle School. Her son, a retired UCSD history lecturer, faces more than seven years in prison if convicted.

His attorney is hoping for probation, which would give his client a chance to pay back the money and make amends for covering up his mother's death 15 years ago.

"He regrets to this day that he did that. And that started the ball rolling on all of this," added Johnson.

Washburn told police his mother wanted to be buried in the backyard, according to the autopsy report.

His attorney is hoping to negotiate a plea bargain during the coming weeks.