A Russian general was killed by a car bomb in southern Moscow on Monday, Russian investigators said, adding that they suspected Ukrainian special services could have been behind the attack.

According to Reuters, the bomb exploded under the Kia Sorento car driven by Lieutenant General Fanil Sarvarov, head of the Russian General Staff’s army operational training directorate, as he left a parking space.

Russia’s State Investigative Committee said Sarvarov had died from his injuries.

Svetlana Petrenko, a spokesperson for the committee, said investigators were gathering forensic evidence, questioning witnesses, and reviewing security camera footage.

“Various versions for the killing are being examined, one of which involves the possible role of Ukrainian intelligence services in organizing the crime,” she said.

Myrotvorets, an unofficial Ukrainian website that provides a database of people described as war criminals or traitors, updated its entry on Sarvarov to say the 56-year-old had been “liquidated.”

A string of high-profile Russian figures have been assassinated during the nearly four-year-old Ukraine War, and Ukrainian military intelligence has said it was responsible for a number of the attacks.