The Polk County Sheriff’s Office is handling the investigation into the deaths, deputies said.
Investigators for the National Transportation Safety Board and FAA have been notified and will investigate the cause of the crash, deputies said.
Although the medical examiner will positively identify the victims, based on interviews with family, friends and witnesses at the Bartow Airport, the Sheriff's Office believes the following five adult victims were on-board the plane:
The pilot, John Shannon, 70, a Lakeland attorney.
John's daughter, Olivia Shannon, 24, of Lakeland, a Southeastern University student.
John's daughter, Victoria Shannon Worthington, 26, a Baltimore school teacher.
Victoria's husband, Peter Worthington Jr., 27, a third-year law student at the University of Maryland.
And family friend, Krista Clayton, 32, a teacher at Jewett Academy in Lakeland.
John Shannon filed a flight plan Sunday morning to fly to Key West. His daughter and her husband arrived in town Saturday for the holidays from Baltimore, where they live. Clayton joined the family on the trip.
All of the victims died upon or immediately after impact. Autopsies will be conducted later this week to determine their exact causes of death.