Moscow police have arrested four suspects linked to the jet accident that killed Total CEO Christophe de Margerie and three others earlier this week.
Vladimir Martynenko, the snowplow operator who allegedly caused the accident, was arrested Thursday.
A preliminary medical examination found that Martynenko was drunk at the time of the accident, Russian news source Tass said.
He will be held in police custody until December 21.
Air traffic controller Alexander Kruglov, senior engineer Vladimir Ledenev and traffic control trainee Svetlana Krivsun were also arrested Friday for their alleged involvement in the crash.
The three airport employees have been accused of neglecting safety standards, the Moscow Times said.
Kruglov has pleaded not guilty.
Krivsun has been placed under house arrest. The two men will remain in police custody.
A fifth suspect, Roman Dunayev, is also being questioned by investigators.
De Margerie, two pilots and a flight attendant died Monday night when the Falcon jet they were riding in collided with a snowplow on a Moscow runway.
The jet went up in flames and crashed onto the runway at Vnukovo airport around midnight local time.
Russian investigators said Martynenkowas was drunk at the time of the accident.
The driver’s lawyer has denied the accusation.
Moscow transportation investigators opened a criminal investigation into possible breaches of safety rules and negligence.
French officials sent three experts to aid in Moscow’s investigation and are also opening a manslaughter investigation.