Petrol giant Chevron claims former Cambodian opposition leader Sam Rainsy and his lawyers have attempted to “besmirch” the company with a “burdensome” request seeking information about the murder of Kem Ley, according to a recent California court document.

Ley, a prominent political analyst, was shot dead in broad daylight on July 10 at a Caltex Starmart, which is owned by the California-based Chevron.

Rainsy was seeking video footage and staffing information at the Cambodian outlet to bolster a case before the International Criminal Court accusing the Cambodian government of human rights abuses, but Chevron has said he and other plaintiffs were “litigating over nothing”.

“[T]he only item of evidence that the Petition specifically argued for – video recordings from cameras at a Phnom Penh service station – had been seized by Cambodian police authorities within hours of the Kem Ley murder,” Chevron’s May 11 court filing said.

The company said it had “provided requested information about the tenure of service station employees that were on-site at the time of the murder”.

The document says Chevron worked for months to cooperate with Rainsy’s requests but that “rather than embrace a reasonable resolution, Applicants escalated their demands and began insisting that Chevron – now – conduct an on-the-ground investigation of events occurring nearly a year ago and 8,000 miles away”.

It adds that an appeal against Rainsy’s defamation conviction in March for his claim that Ley’s murder was “state-sponsored terrorism” does not “salvage” his application and the subpoena should be rejected.

“Applicants also offer no explanation as to how any internal Chevron documents that Chevron might have reacting to the event could have any bearing on an appeal regarding the truth of a statement contending that the murder was ‘state sponsored’,” the company wrote.

Rainsy and his lawyers did not respond by deadline yesterday, but in a May 4 filing, they claimed Chevron had used “spurious theories” to “throw sand into the gears of discovery”.