The United Arab Emirates is formally treating the attack aboard Flydubai Flight FZ1073 as terrorism. UAE Attorney General Hamad Saif Al Shamsi said the co-pilot “attempted to carry out a terrorist act,” and investigators are examining whether there was prior planning, outside direction, or additional help.

An initial assessment by Israeli security officials is that the co-pilot acted alone. Investigators are still working to determine whether he had ties to terror groups or accomplices.

According to intelligence and law enforcement officials who spoke with ABC News, the co-pilot, Hamam Al Hammami, a 29-year-old Omani national, had previously been identified as a security risk and suspended from flying at Oman Air.

Australia has opened its own investigation. The Australian Federal Police and the ASIO security service are examining the period Al Hammami spent in Australia, including whether he was radicalized there.

The Associated Press reported that the UAE gave Israel details on the flight crew in advance, including names and nationalities. Israel’s Transportation Ministry says the pilots’ names were not passed to it and that background checks on foreign pilots are not its responsibility.

Israeli teams are involved in the probe. The Mossad is reported to be leading the Israeli side, and Israel is expected to take part in the co-pilot’s interrogation. Security officials said a preliminary summary of the Emirati investigation is expected to reach Israel in the coming days.

Reuters recreated the plane’s dive in a simulator. According to the reconstruction, the autopilot disconnect and a descent of roughly 16,000 feet in about half a minute produced extreme loads, which a flight expert compared to a “vertical roller coaster.” The 737 MAX 8 withstood the forces and landed safely.