When Gretchan Pearce got a call from her sister-in-law Monday evening, Mary Pearce said her son was having "an episode" and she needed help at her home in the upscale Harbour Point Yacht Club neighborhood off Dawsonville Highway.

By the time Gretchan Pearce drove to her sister-in-law's home less than a mile away on Sunset Point Drive, 64-year-old Mary Pearce was dead.

Her son, John Pearce, met Gretchan in the foyer naked, covered in blood and wielding a knife, according to details released Tuesday by the Hall County Sheriff's Office.

"She was stabbed. She retreated to her car, couldn't get away from him ... and then she ran up the hill up the driveway and across the street to the neighbor's house," said Col. Jeff Strickland, chief deputy with the sheriff's office.

John Pearce, 29, later was killed by deputies in a cul-de-sac outside the home.

Authorities say Gretchan Pearce, 66, is in critical condition at Atlanta Medical Center, but they expected her to survive the multiple stab wounds.

According to the information gathered from the sheriff's office and 911 dispatch, neighbors who lived across the street from Mary Pearce called 911 at 8:23 p.m. when Gretchan Pearce fled to their home.

The neighbors locked the doors and waited for deputies to arrive, according to dispatch records.

The first two deputies, who have not been named, arrived 11 minutes later, dispatch records show.

Witnesses pointed deputies toward a driveway next door to Mary Pearce's home, where deputies found John Pearce "walking up the driveway nude and heavily covered in blood," according to a news release from the sheriff's office.

What happened next remains under investigation by the Georgia Bureau of Investigation. Dispatch records say shots were fired at 8:35 p.m.

Neighbor Carol Baker said she and her husband were in their computer room when they heard shots. They went to the front door, saw sheriff's deputies and John Pearce, who subsequently fell at the edge of their driveway.

Authorities are awaiting results of an autopsy of John Pearce's body.

The GBI is trying to determine what transpired between deputies and the man before they shot and killed him.

Strickland said he could not comment on whether John Pearce was holding a weapon when deputies encountered him Monday night.

The two deputies involved have been placed on administrative leave pending the results of the state-level investigation, which Strickland said is standard procedure in all officer-involved shootings.

Prior to Monday, Baker said she and her husband often saw John Pearce, who lived with his mother, and that he seemed "creepy."

A news release from the sheriff's office referred to him as a "deranged perpetrator" who they believe intended to set his mother's house on fire after killing her.

They believe those plans were interrupted by the arrival of Gretchan Pearce, whose champagne-colored Infiniti still sat Tuesday in Mary Pearce's driveway with the driver's side door open.

Hall County investigators say approximately 20 gunshots had been fired inside Mary Pearce's home, and the first floor was covered in blood.

Investigators found a small-caliber handgun inside the house along with what appeared to be multiple kitchen knives.

Knives were also found in the driveway, Strickland said.

"There are several knives that were involved in this," Strickland said.

Mary Pearce's death is the first homicide reported in Hall County this year. It occurred in an unlikely area where authorities say they have had few problems in the past.

Strickland said the sheriff's office has no record of previous problems at the home where neighbors say Mary Pearce moved in March 2010.

John Pearce had also never been arrested in Hall County.

"That's a very affluent neighborhood that we have very little issues in," Strickland said.

Both the sheriff's office and the GBI will continue their separate investigations into the incident this week.

Staff writer Jeff Gill contributed to this report.