ST. LOUIS (AP) — A Missouri woman who admitted scheming and setting a string of arson fires with her ex-husband to bilk hundreds of thousands of dollars from insurers was sentenced Thursday to eight years in federal prison for her role in a 2001 blaze that killed their 15-year-old son.

Sandra Kay Bryant, 59, will serve slightly less than half of the prison term imposed because U.S. District Judge Audrey Fleissig credited her with the four years and two months Bryant spent in jail years ago on state charges linked to son Zachariah Kemper’s death.

Authorities have said the teenager died in the family’s home in the St. Louis suburb of Florissant after becoming trapped in the basement he shared with Bryant while her mother, her ex-husband, Steven Kemper, and his lover lived upstairs. The adults were unharmed. Investigators say Bryant set fire to a trash can in a utility room next to her son’s bedroom, using hairspray to fuel the flames.

Bryant pleaded guilty in March to a federal felony count of aiding and abetting the use of fire to commit mail fraud, unequivocally acknowledging her participation in the plot to profit from arson blazes. She initially was charged in state court with an arson-related murder count but walked free after a judge declared a mistrial, barring Missouri prosecutors from going after her again.

Federal prosecutors took over the case and, after the couple was indicted in 2011, characterized Kemper and Bryant as greedy, cash-strapped schemers who once tried to torch the Alton, Illinois, home of Bryant’s mother after siphoning $30,000 from her bank accounts. They divorced in 2002.

Kemper, who pleaded guilty in 2013 to a felony count of aiding and abetting the use of fire to commit mail fraud, has blamed Bryant for their son’s death, insisting during last month’s sentencing hearing that he wanted the fire to take place while no one was home. Fleissig dismissed that, noting Kemper’s penchant for arson with the intent to cash in on insurance.

“To suggest you are in a position to control what would happen once you set those wheels in motion is naive,” Fleissig told 56-year-old Kemper before ordering him to spend five years and 10 months in prison. “You may not have anticipated that your son would pay the ultimate cost.”

Kemper is free on bond until the U.S. Bureau of Prisons orders him to report to a designated lockup. That assignment still was pending Thursday.