PORT RICHEY — It could take weeks to positively identify five people thought to have died in Wednesday's Tampa-bound plane crash in the Gulf of Mexico, authorities said.
Fragments of human remains were found among wreckage in the gulf Thursday morning, and identifying them will require DNA samples from family members, said Bill Pellan, investigations director of the Pinellas-Pasco Medical Examiner's Office.
The Coast Guard officially called off its search for the people at 3 p.m. Thursday.
Relatives from Texas, Arizona and Florida were on their way to the Medical Examiner's Office to submit samples.
"It could take a week or weeks, depending on when we get the samples," Pellan said. "One of our highest priorities is to establish the identity of the remains we have."
Officials from the National Transportation Safety Board also have opened an investigation to determine what went wrong, spokesman Terry Williams said.
Coast Guard Capt. Timothy Close said that judging by the way wreckage was spread over a wide area, it appeared to be a catastrophic crash.
One of the passengers on the Cessna 421 was an employee of McNichols Co., a perforated steel business headquartered at Rocky Point Drive in Tampa, said company human resources manager Sarah Morris. She would not identify the employee.
"All I can tell you is we're monitoring the rescue," Morris said.
Two of the people aboard the plane were 40-year-old Roland Schurrer, president of Quality Powder Coating in Carrollton, Texas, and 33-year-old Steve Barrows, a marketing representative and company pilot.
The other two people on the plane were also employees of the company, which coats metal products. Their identities have not been released because families have not been notified.
Two dogs, believed to belong to Schurrer and Barrows, also may have been on the plane, officials said.
The Coast Guard cutter Alligator found remains and wreckage overnight in a 2-mile debris field after a helicopter spotted a seat from the plane.
The plane is registered to Q4 Aviation LLC of Carrollton, which also goes by the name Quality Powder Coating.
Quality Powder spokesman Andy Brown said those on the plane were headed to a meeting in Florida for a couple of days.
The twin-engine Cessna 421 was headed to Tampa International Airport and crashed about 20 miles west of Port Richey. It left from Collin County Regional Airport in McKinney, Texas, at about 10 a.m. Central Standard Time. A Jacksonville air traffic controller lost contact with the plane about 3 p.m. Eastern time.
Forecasters reported several thunderstorms in the area at the time the plane went down.
Federal Aviation Administration spokesman J. Lynn Lunsford said the pilot of the plane "reported heavy turbulence, loss of control and inverted flight" while flying at about 5,000 feet.
Lunsford said Barrows had no accidents or enforcement actions on his record.
Times staff writer Kameel Stanley and the Dallas Morning News contributed to this report.