A Learjet carried nine people.

It crashed in South Florida on Sunday.

It exploded.

A federal investigator spoke on Monday.

He said the plane likely broke apart before it hit the ground.

Passersby made videos.

The videos showed the jet in a fast dive.

The jet was going to the Bahamas.

It exploded in Greenacres.

Greenacres is about 7 miles (11 kilometers) southwest of West Palm Beach.

The victims included the co-pilot.

Her name was Nathalia Gadelha Filgueiras.

She was 20 years old.

The victims also included Adam Robinson.

He was a technology entrepreneur.

His wife Helen Sharp was on the plane too.

Their two young children were with them.

Relatives said this.

Tom Chapman is a member of the National Transportation Safety Board.

He said investigators found evidence.

The aircraft started to break up before it hit the ground.

Debris could spread far and wide.

Jeff Guzzetti is a former investigator.

He worked for the NTSB and the Federal Aviation Administration.

He said key parts of the jet's tail may be lost.

They may be lost in turbulence.

They may be lost during the dive.

Then the plane was impossible to control.

He said this could explain the missile-like path.

The plane looked like a missile just before it hit the ground.

Chapman said weather will be a major focus.

Investigators will study the weather.

Rain hit the region on Sunday.

One pilot spoke to air traffic control.

He spoke about icing at high altitude.

At the time of the crash, the FAA warned pilots in the area.

The FAA warned about nearly stationary thunderstorms.

Cloud tops reached up to 45,000 feet.

AccuWeather reported this.

Chapman said investigators still need to find the conditions at 35,000 feet (11,000 meters).

The pilot began reporting problems at that altitude.

John Cox is a retired airline pilot.

He said the conditions would have terrified him.

The pilot described turbulence.

He described liquid precipitation.

It froze on the plane at negative 47 degrees Celsius.

Cox said precipitation at that altitude and temperature is usually ice crystals.

They simply go around the plane.

He called the reports big red flags.

Chapman said the plane first had a cockpit voice recorder.

Investigators hope to find it.

Timothy Monville is an NTSB investigator.

He said the scene work will take several days.

The biggest problem will be moving the major wreckage.

It is in a crater on the roadway.