A Missouri woman who authorities said schemed with her ex-husband to defraud hundreds of thousands of dollars from insurers with house fires pleaded guilty Thursday for her role in a 2001 blaze that killed the couple's 15-year-old son.

Sandra Kay Bryant, 59, pleaded guilty in federal court in St. Louis to one felony count of aiding and abetting the use of fire to commit mail fraud. Bryant could be sentenced to up to 10 years in prison in June.

Her ex-husband, Steven Kemper, pleaded guilty to the same charge in 2013 and will be sentenced next month.

Investigators said the fire at the family's home in the St. Louis suburb of Florissant killed Zachariah Kemper after he became trapped in the basement he shared with his mother while her mother, Kemper and his lover lived upstairs. All of the adults escaped unharmed.

According to prosecutors, Bryant set fire to a trash can in a basement utility room next to her son's bedroom, using hairspray to fuel the flames. Bryant and Kemper knew their son was asleep in the next room, the indictment alleges. Firefighters found the boy's body near his bed. His arms were covering his head and face, and a fire extinguisher was on the floor, a few feet away.

The teen sustained burns on his upper body, head and extremities, according to an autopsy that found soot in his airway, showing he was alive when the fire broke out.

Bryant was initially charged in state court with an arson-related murder count, but she walked free after a judge declared a mistrial, barring Missouri prosecutors from going after her again.

The federal indictment characterized the couple as greedy, cash-strapped schemers who once tried to torch the Alton, Illinois, home of Bryant's mother after secretly siphoning $30,000 from her bank accounts.

Betty Bryant, who the indictment said also managed to escape a New Year's Day 1997 blaze authorities say Kemper had set in her St. Louis home as she slept, later denied the couple any more financial help while threatening to cut them out of her will. She died in 2007.

Kemper and Bryant divorced in 2002.