A Moscow court on Wednesday handed a 21-year prison sentence to a physicist accused of treason, attacking critical infrastructure and plotting sabotage, state media reported, citing official sources.

Artyom Khoroshilov, a 34-year-old researcher at the Moscow Institute of General Physics, was also fined 700,000 rubles ($9,158) and will serve the first five years of his term in a high-security prison. Prosecutors had asked for an even harsher punishment: 25 years in a penal colony. In April, Khoroshilov was added to Russia’s list of terrorists and extremists.

Khoroshilov was arrested in August 2024 and charged with treason for transferring more than $9,000 to a Ukrainian charity foundation that supports the armed forces. He admitted making the transfers, saying he intended to help relatives and civilians in the Kyiv region and mistakenly donated to organizations supporting Ukraine’s military.

Prosecutors also accused Khoroshilov of keeping components for an explosive device and photographing rail lines near a military unit. He said the chemicals were for gardening and denied knowing the tracks he photographed were connected to any military facility.

Police said Khoroshilov carried out a distributed denial-of-service attack (DDoS) on Russian postal systems in August 2022 using software allegedly found on his home computer. His co-workers told local media the accusations made little sense, claiming he “barely knew how to program” and could not have orchestrated such an attack.

The IT Army of Ukraine, a hacktivist group known for coordinating DDoS attacks on Russian infrastructure, said on Telegram it did not know whether Khoroshilov was involved with them but argued Russian authorities “hunt down any sign of resistance.”

Khoroshilov acknowledged downloading and running software used for DDoS attacks but denied communicating with the IT Army.

Since the start of the war, Russia has stepped up prosecutions over alleged cyberattacks linked to Ukraine. In April, a man was sentenced to two years in a penal colony for a DDoS attack on a tech firm designated as critical infrastructure. In October, the FSB security agency detained a 61-year-old Moscow resident accused of using Ukrainian software to disrupt regional elections.

Separately, investigators last autumn opened a treason case against another Moscow-based scientist over alleged cooperation with Ukrainian intelligence, while a student and a 49-year-old man were arrested in two other cases involving suspected support for Ukrainian hacktivist groups or cyberattacks on energy infrastructure.