ADRIAN, Mich. (AP) — Authorities say a southeastern Michigan plane crash that went unreported for more than four hours left 2 people hurt.

Lenawee County Undersheriff Troy Bevier says the crash occurred about 10 a.m. Friday about a mile from the Lenawee County Airport outside Adrian but went undetected until about 2:20 p.m., when a woman passenger managed to walk to a nearby road and flag down a motorist who called 911.

Bevier says the woman and a man both suffered serious injuries and were transported to a hospital. Their names haven't been released.

Bevier says the single-engine plane broke apart in the crash, with part of it caught in a tree.

He says the cause of the crash wasn't immediately known and the Federal Aviation Administration is sending investigators to the crash site.