Associated Press

Detroit officials will post signs on 5,000 abandoned homes and recruit volunteers to monitor them over the three-day Halloween period as part of an annual effort to prevent arsons.

The Detroit mayor's office says the signs are a warning to any would-be arsonists that people will be patrolling neighborhoods on the so-called "Angels' Night."

Angels' Night has been credited with drastically reducing the number of intentionally set fires at the end of October.

It's a long-running response to what was known as Devil's Night, the day before Halloween. In 1984, Detroit had more than 800 fires during the period.

Last year, 95 were reported.