Earlier this month, two Russian cosmonauts conducted a spacewalk to investigate the mysterious hole in a capsule docked to the International Space Station.

On Monday, one of the cosmonauts, Sergei Prokopyev, said that the opening was drilled from inside the Soyuz capsule visiting the space station.

He also said law enforcement agencies in Russia are now probing into what caused it.

Prokopyev, who is now back on Earth, said investigators were looking at the samples that he and crewmate Oleg Kononenko collected during the nearly eight hours spacewalk on Dec. 12.

Prokopyev said at a news conference that the cavity stemmed from the interior of the capsule. He said it will be up to the investigative organs to judge when the hole was made.

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