By Alex Dobuzinskis
LOS ANGELES (Reuters) - U.S. authorities on Monday sought to determine what caused a small plane to plummet shortly after take off, break apart and destroy a house in Yorba Linda, California, killing five people including the pilot.
The National Transportation Safety Board (NTSB) gathered wreckage from Sunday's crash, which left pieces of the aircraft spread across a four-block area, as questions surrounded the pilot of the aircraft.
The pilot was Antonio Pastini, 75, a resident of Gardnerville, Nevada, who was a retired Chicago police officer, Orange County Sheriff's Department Lieutenant Cory Martino said at a news conference.
But Chicago Police Department spokeswoman Carrie Costanzo later said by phone her agency had no record of Pastini having been an officer with the department.
Representatives for the Orange County Sheriff's Department could not be reached for comment late on Monday.
Moments before the crash, the twin-engine Cessna 414 reached an altitude of about 7,800 feet (2,400 meters) before plummeting to the ground, NTSB investigator Maja Smith said.
"A few witness reports say they saw the airplane coming out of a cloud at a very high speed before parts of the airplane such as tail and then subsequently wings started to break off," Smith said. "So we're dealing with an in-flight break-up."
The pilot had taken off from nearby Fullerton Municipal Airport in Yorba Linda, about 35 miles (56 km) southeast of Los Angeles, officials said.
Residents have told local media the crash sounded like an explosion. But Smith said witnesses have not reported seeing any detonation while the plane was in the air.
Pastini is the only victim of the crash who has been identified.
Authorities planned to use DNA evidence to identify the two men and two women who died after the bulk of the wreckage hit a house they were in and the structure burst into flames, Martino said.
It was not immediately clear if the four people lived at the house or were guests there, he said.
Two other people were hospitalized with moderate burns.
Pastini's daughter Julia Ackley, a resident of the Los Angeles suburb of Torrance, told the Los Angeles Times her father regularly flew a plane between Nevada and Southern California to visit family.
(Reporting by Alex Dobuzinskis in Los Angeles, Peter Szekely in New York and Rich McKay in Atlanta; Editing by Cynthia Osterman and Rosalba O'Brien)