Follow CBSPHILLY Facebook Twitter

TREDYFFRIN TOWNSHIP, Pa. (CBS) — Criminals have found a new way to snatch high-valued items by using just a flypaper on a line to “fish” envelopes with checks right out of U.S. Postal Service mailboxes.

READ MORE: Philadelphia To Begin Offering Children Ages 12-15 Pfizer's COVID-19 Vaccine On Thursday After CDC's Recommendation

Tredyffrin Township Police say the thieves search for envelopes containing checks destined for utility or credit card companies for account payments. Then they use certain chemicals and “wash” the ink from the stolen checks, and rewrite the checks out to themselves.

The checks are quickly cashed at banks and usually the victims don’t realize they’ve been robbed until they receive a past due notice because their payment never arrived.

READ MORE: Gasoline Shortage Appears To Be Creeping Into Philadelphia Region As Colonial Pipeline Resumes Operations

Authorities are investigating one of these incidents reported by a resident of Tredyffrin Township and there have been reports of similar incidents in surrounding areas.

The U.S. Postal Inspection Service has recommended several things people can do to avoid falling victim to this scheme including:

  • Consider making your payments electronically
  • Drop envelopes containing payment checks or other person information inside at your local Post Office; if you do use outside boxes, or leave them in your home box to be collected, try to deposit mail shortly before the scheduled pick-up time.
  • Write checks out with pens containing pigmented ink, they’re harder to wash without damaging the check.

If you see something suspicious in your area, officials are asking that you call so they can investigate.

MORE NEWS: Man Shot 11 Times, Killed In Southwest Philadelphia Quadruple Shooting, Police Say

If you think you’ve fallen victim to this scheme, contact your local police department or United States Postal Inspection Service officer for assistance.