Authorities: Ark. woman stabbed granddaughter, 7, and set home on fire in murder-suicide

(CBS/AP) CONWAY, Ark. - The fire that killed an Arkansas woman and her granddaughter whom she adopted after her son's death in Iraq appears to be a murder-suicide, authorities said on Monday.

Authorities say Janice Robbins, 63,  left a suicide note in her pickup truck on Saturday before stabbing 7-year-old Abby Robbins in the chest and setting fire to their home. In the note, Robbins wrote that she didn't want to leave the girl behind and begged, "Please pray for my soul."

According to the county coroner, it was smoke from the fire that killed both Abby and her granddaughter. Authorities found a gas can next to each of the bodies inside the home, about 30 miles from Little Rock, which was engulfed in flames by the time firefighters arrived early Saturday morning.

Along with the suicide note, Robbins taped an envelope with keys to the side of the truck so authorities could get inside, Faulkner County sheriff's spokesman Maj. Andy Shock said. She also left a plastic bin in the truck that contained her will, Abby's birth certificate and other personal effects.

Abby's father, Army Staff Sgt. William T. "Terry" Robbins, was shot and killed by a fellow soldier in Iraq in 2005 during a dispute over alcohol. Janice Robbins finalized her adoption of Abby in 2010.

Relatives told investigators that Robbins, a nurse who retired from the Army in 2005, struggled with depression after her son's death, coroner Patrick F. Moore said. Authorities said she had another son who died a few years earlier.

Maj. Shock said investigators were trying to find out if Robbins had been getting counseling for depression.

Investigators are awaiting the results of toxicological testing, which would show if she was taking medication and whether she gave drugs to the young girl before setting the home on fire. Those tests will likely take weeks.