Five people were killed last week when a small plane crashed in a rural area of southern Georgia. 

Now, federal investigators say the pilot was unlicensed and flying a homebuilt aircraft. A witness told authorities she saw the plane flying erratically just above the tree line before it went down at 3:40am ET. 

In a preliminary report from the NTSB, investigators identified the pilot as a local farmer named Waylon Boatright, 38, and said his four passengers were close friends. 

They said it's unclear why the group was traveling in the middle of the night. No flight plan was filed before Boatright took off from a small airport in Bacon County.

Authorities are hoping cell phones recovered in the wreckage of the four-seat RV-10 will yield some clues. 

AP reported

The RV-10 is a single-engine aircraft sold in kit form to be assembled by the buyer. The NTSB report said Boatright had been certified to build and repair the plane in December 2010, but he was not licensed to fly it.

Boatright "did not hold a pilot certificate and no pilot logbook was recovered," the report said. "Therefore, the pilot's total flight experience could not be determined."

Evidence from the crash site showed the plane smashed into trees 50 feet above the ground before slamming into the dirt. Wreckage was scattered across a path 200 feet long.