VERO BEACH, Fla. -

Authorities are searching for a missing British pilot off the coast of southeast Florida.

The Martin County Sheriff's Office and the U.S. Coast Guard continued their search Tuesday for Andrei Postelnicu. He left Marathon in the Florida Keys on Friday and was scheduled to land in Vero Beach that evening. His plane was reported missing the next day.

Authorities say debris recovered along the beach included pieces of the missing Piper Seneca. A local resident found a backpack with identification and other items belonging to Postelnicu. A boot that washed ashore Sunday afternoon also matches his same European size.

Authorities say search efforts have been challenging due to rough waters, windy conditions and the large perimeter of the search.