Island Express Helicopters, the company that owns the aircraft that crashed Sunday, has suspended flight operations, an employee at the company told CBS News. The accident killed Kobe Bryant, his daughter Gianna, the pilot and six other passengers. The employee said the suspension is "for operations reasons," and that the company will decide "day by day" how long it will last.

Island Express is known for flights to and from Santa Catalina Island, according to The Associated Press. The pilot of the doomed helicopter had more than 8,200 hours of flight time and was certified to fly solely using instruments — a more difficult rating to attain that allows pilots to fly at night and through clouds.

Investigators said the twin-engine Sikorsky S-76 banked left and abruptly descended at speeds of up to 5,000 feet per minute in its final 12 seconds, before crashing into a California hillside. The helicopter did not have a terrain avoidance system or a black box, though officials investigating the case did find some clues in the wreckage, including an iPad and maintenance records.

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"This was a high-energy impact crash," a National Transportation Safety Board member said earlier this week. She said preliminary investigations show the helicopter "was in one piece when it impacted terrain," rather than breaking up on its descent. The flight was only a few minutes from its destination.

In this photo taken January 27, 2019, NTSB investigators Adam Huray and Carol Hogan examine wreckage as part of the NTSB's investigation of the crash of a Sikorsky S76B helicopter near Calabasas, California. NTSB / James Anderson

About 35 minutes after takeoff, pilot Ara Zobayan asked air traffic control to track him on radar — but he was reportedly flying too low in the deteriorating weather.

Four minutes later, Zobayan radioed that he was climbing to "go above the layer" of clouds. He reached 2,300 feet in the potentially blinding fog.

Investigators in California said they have since removed all wreckage from the crash site as they work to solve the tragic mystery.

Kris Van Cleave contributed reporting.