The president and co-owner of anexed Crimea’s largest gas station network has been detained on suspicion of large-scale fraud, the RBC news website reported Thursday, citing two individuals familiar with the matter.

Sergei Beym, who leads the fuel distribution company TPP, was taken into custody by law enforcement authorities earlier this week.

He previously headed the Ukrainian state oil and gas company Chernomorneftegaz from 2014-2015 and served as a deputy in the Crimean Supreme Council between 2006-2010.

One source told RBC that Beym is a suspect in a criminal case involving fraud on a particularly large scale, a charge that carries a prison sentence of up to 10 years.