ROGERS, Ark.—Rogers police say they’re mystified as to the source of debris in a neighborhood that is being pelted after dark with metal and glass objects.

Residents of the neighborhood say the debris has included nuts, bolts, chunks of rebar, marbles and ball bearings. Police have received dozens of calls about the flying debris, which has broken out vehicle windows and caused other property damage.

Resident Kevin Montondo says the nightly barrages began last summer and ended for a time after school started, but resumed again around the beginning of June. He says he and others have stationed themselves throughout the neighborhood, trying to determine the source of the debris.

Rogers police spokeswoman Angel Murphy-Pearce says authorities are doing everything they know how to do to locate the source.