Authorities in Russia have arrested a 77-year-old researcher at a Russian rocket- and spacecraft-design institute on treason charges.
Ksenia Pervovlasenko, a spokeswoman for Moscow's Lefortovo district court, said on July 15 that Sergei Meshcheryakov was placed under house arrest.
No more details were provided.
According to MBKh media news agency, investigators searched Meshcheryakov's office and home on July 11.
Meshcheryakov worked with Viktor Kudryavtsev, a 75-year-old researcher at the Central Research Institute for Machine Building.
Kudryavtsev was arrested in July 2018 on suspicion of passing classified data on hypersonic technology to a research group in Belgium.
Kudryavtsev suffered a heart attack while in custody and was transferred in May this year from Moscow’s Lefortovo detention center to a hospital to undergo medical tests.
It is not clear if Meshcheryakov's arrest is linked to Kudryavtsev's case.
Earlier in June, Kudryavtsev's former associate Yaroslav Kovalyov was arrested and charged with high treason as well.
On July 12, the Moscow-based Memorial human rights center declared Kudryavtsev a political prisoner.
In recent years, several Russian citizens have been accused of treason or disseminating classified or sensitive information.