A Montgomery County mom is accused of torching the home of her neighbor -- a detective -- in retaliation for her son's arrest.

Donna M. Krupp, 52, was taken into police custody Thursday, the same day the detective's Lower Pottsgrove Township house was set on fire.

The arson appears to be the culmination of six months of resentment, according to court records.

Investigators say Krupp blamed Limerick Detective Ernie Morris for her son's June arrest by Pennsylvania state police. Although Detective Morris was not involved in the case, investigators say Krupp was convinced he told state police where to find her son, Joshua Beauseigneur, who was wanted for an outstanding traffic violation.

Krupp was so angry, police say they warned her to stay away from Morris. The detective also hired an attorney to essentially tell Krupp if she couldn't act neighborly, to ignore Morris and his wife. Instead, she allegedly continued to confront the detective, often late at night when he returned home from work.

"When her son was arrested, she couldn't accept that and that's when she started the other harassment," said neighbor Terri Pope.

In November, Morris installed a video surveillance system after someone egged his car and put sugar in the fuel tank. Investigators say those same cameras captured Krupp setting fire to the detective's porch Thursday while he and his family were away at Disney World. The home was engulfed when firefighters arrived.

Krupp, 52, was charged Friday with arson, recklessly endangering another person, risking a catastrophe and possession of an instrument of crime. Her bail was set at $1 million cash bail.