Russian mercenary Yevgeny Prigozhin’s plane was visible on radar until the last 30 seconds, Reuters reports.

No sign of trouble until a sharp drop and crash in the last 30 seconds the aircraft showed Embraer ( EMBR3.SA ) Legacy 600, which Evgeny Prigozhny was reportedly on board, according to flight tracking data.

Rosaviatsia, Russia’s air traffic service, said Prigozhin, who led the mutiny in June, was one of 10 on board the plane that crashed. He was traveling from Moscow to St. Petersburg when it happened near the village of Kuzhenkino in the Tver region, the Russian Emergencies Ministry said.

At 3:19 p.m. GMT, the aircraft made a ‘sudden vertical descent, said Flightradar24’s Ian Petchenik. Within about 30 seconds, the aircraft had plummeted more than 8,000 feet from its flight height of 28,000 feet.

“Whatever happened, happened quickly,” Petsenik said.

“They may have been struggling with some sort of aircraft problem during the duration,” Petsenik said. But before its dramatic crash, there was “no indication that there was any problem with this aircraft”.
The video showed the plane descending rapidly with its nose pointing almost straight down, leaving smoke in its wake.

Russian investigators are conducting a criminal investigation to determine what happened. Anonymous sources told Russian media they believed the plane was shot down by one or more surface-to-air missiles. Reuters could not confirm this.

Brazilian plane maker Embraer SA ( EMBR3.SA ) said it had not provided any service or support in recent years to the plane, which has about 13 seats.

The company said in a statement that it complied with international sanctions imposed against Russias. The luxury jet was identified on Flightradar24 as registration RA-02795, the same as the plane that carried Prigozhin to Belarus after the mutiny, a source familiar with the matter said.

Online flight tracker Flightradar24 last recorded the aircraft’s location at 3:11 p.m. GMT, before the crash. Some interference in the area probably slowed the collection of further location data.

Other data continued to be recorded for nine minutes. Flightradar24 said the jet made a series of climbs and descents of a few thousand feet each over 30 seconds before its final descent. Flightradar24 received the final data on the jet at 3:20 p.m.