ALLEN PARK, Mich. (AP) - Did you miss a letter last fall? Investigators say they discovered 1,800 pieces of first-class mail that was headed for recycling in suburban Detroit. The Postal Service inspector general says the mail was found in a trailer in March at an Allen Park facility, mixed with undeliverable bulk business mail. Some of the first-class mail was postmarked months earlier in November. Coincidentally, inspector general staff were checking the accuracy of delayed mail reports at major distribution centers in Allen Park, Pontiac and Lansing. Postal Service spokeswoman Elizabeth Najduch says the first-class mail was recovered and delivered. She says the Allen Park center gets undeliverable business mail for recycling from more than 270 post offices. It's typically ads, catalogs and fliers. She says corrective steps have been taken.