Authorities continued an investigation Sunday into why a small plane crashed in a rural residential area as its pilot prepared to land, killing four people.

A story from the AP says, the crash killed the pilot, David Eckstein, 67, of Mansfield, and his three passengers: John McCarter, 68, and Karen Saprano, 62, both of Mansfield, and Janet Hanna, 66, from Shelby, State Highway Patrol spokesman Sgt. Carlos Smith said Sunday.

Eckstein was a member of Tiffin University's board of trustees, a university statement said. Hanna was an English professor at Tiffin and became dean of the university's School of Arts and Sciences in 2005 before retiring the next year. The two were married in 2005.

Eckstein is the retired former owner of Edge Plastics in Mansfield. McCarter and Saprano were married in 2006 in a plane flown by Eckstein.

The plane departed from Mansfield, but investigators still do not know what caused the crash, Smith said. "Obviously, something happened on the descent," he said.