A leader of Russian separatist forces in eastern Ukraine, Igor Girkin, was formally accused Wednesday for plotting to shoot down the Malaysia Airlines flight MH17 in July last year that killed all 298 people on board. A writ filed against him in Chicago claimed that Girkin was being supported by the Russian government when he shot down the plane.

The case was brought on behalf of families of 18 victims on the plane, including six British people, and claimed $900 million. Girkin gained attention after a social media page with which his group, the self-proclaimed Donetsk People’s Republic (DPR or DNR), was linked, allegedly claimed responsibility for taking out a Ukrainian An-26. “We warned them - don’t fly in our sky,” it said in a post, the Telegraph reported. The post was later removed, but led to allegations that Girkin’s men may have shot down the MH17 plane by mistake. However, DPR denied responsibility for the attack.

“Flight 17 flew over the airspace of the area in which the aforesaid rebel army was waging its war activities and the rebel army under the command responsibility of defendant Girkin shot down the subject Boeing 777-200 aircraft,” the court papers said, according to the Telegraph.

The lawsuit added that Girkin “ordered, aided and/or abetted this action and/or conspired with those persons who fired the missile or missiles,” and individuals under his command “took responsibility” for shooting down the plane.

The missile that brought down the plane came to Ukraine from Russia, the suit reportedly claimed. The plane was traveling from Amsterdam to Kuala Lumpur, and was shot down while it was passing through eastern Ukraine.

“Defendant Girkin acted with the actual or apparent authority of individuals in the Government of Russia,” the lawsuit stated, according to the Telegraph.

Lawyer Floyd Wisner brought the case against Girkin in an American court by employing the U.S. Torture Victim Protection Act that can be used against foreign nationals.

“It is not about money, it is about getting answers from Girkin and putting pressure on Russia to cooperate with the international tribunal,” Wisner reportedly said, adding: “There is no cost to the families. We are doing this as a service to them and they want some answers and they don’t want to be forgotten.”

A case was also filed against Malaysia Airlines on behalf of Reine Dalziel, whose husband Cameron died in the crash. It alleged that the airline was negligent because it planned a trip over an “internationally recognized conflict zone.” The route at the time was banned for U.S. airlines and was also being avoided by several other companies, including British Airways. Cameron had reportedly bought the ticket in the U.S. 

Malaysia Airlines reportedly declined to comment on the case.

Australia, Belgium, Malaysia, the Netherlands and Ukraine have come together to put forth a joint proposal to set up an independent tribunal to “try those responsible for crimes” related to the MH17 disaster. While Dutch investigators are set to release a final report of their investigation into the crash in October, a preliminary report released last September said that the plane was brought down by a “large number of high-energy objects that penetrated the aircraft from outside.”