A Moscow court sentenced leading Russian hypersonic flight scientist Alexander Shiplyuk to 15 years in a maximum-security prison on charges of treason, the independent news website Mediazona reported Tuesday.Shiplyuk, 57, headed Siberia’s Institute of Theoretical and Applied Mechanics and was one of three institute members arrested between 2022 and 2023 on suspicion of treason.

Earlier reporting suggested that Shiplyuk was accused of sharing classified materials at a scientific conference in China in 2017.The Moscow City Court found him guilty of treason and handed down a 15-year prison sentence.

Shiplyuk denied the charges, insisting that the information he was accused of sharing was publicly available online.Shiplyuk’s colleague, Anatoly Maslov, was also convicted of treason in May and jailed for 14 years.

Alexander Kuranov, who headed a St.

Petersburg-based research institute, received a seven-year sentence in April.Kuranov reportedly secured a more lenient sentence by testifying against Maslov.

The BBC’s Russian service reported Tuesday that Shiplyuk refused a plea deal.Shiplyuk’s trial was held behind closed doors due to the sensitive nature of the case, with prosecutors initially seeking a 20-year sentence.Russia has ramped up treason convictions since its annexation of Crimea in 2014 and the full-scale invasion of Ukraine in 2022.

According to the BBC’s Russian service, 11 Russian scientists working on hypersonic flight have been jailed or arrested since President Vladimir Putin touted a new generation of weapons in 2018.