In April, Oleg and Igor Minin, former scientists at the Siberian Institute of Applied Physics, were accused of revealing state secrets in a monograph they wrote about their research, Novosti reported.

But after investigation, Russia’s Federal Security Service withdrew charges against the Minins saying “there was no sufficient evidence” they had given away sensitive information.

Attorneys for the Minins argued everything contained in the monograph was available from unclassified sources, Novosti said.

This case is similar to last year’s accusations against researcher Oleg Korobeinichev, head of combustion kinetics laboratory at the Novosibirsk Institute of Chemical Kinetics and Combustion. The security service publicly apologized to Korobeinichev after investigating whether classified information was contained in an academic paper.