John Gruner was an arsonist and murderer. He set his ex-wife Emily's apartment on fire in an attempt to kill her and take custody of their daughter Hannah, but instead, a firefighter, Sean Grafton, was killed. It was later revealed that the firefighter was shot by an abandoned gun that discharged due to the heat of the fire.
Gruner was charged with arson and felony murder, receiving a sentence of 25 years to life. (L&O: "In God We Trust")