Anatoly Maslov, 76, is one of three hypersonic missile scientists who worked at an institute in Novosibirsk and who are now facing what the Kremlin has said are "very serious accusations."
Kyiv claims its US-supplied air defense systems have been able to shoot many of the missiles down, leading to the Kremlin's harsh response.
Integrated multi-layered air defenses are increasingly key to defending countries and cities. Both Israel and Ukraine are now showing this.
Russia claims to have destroyed a Patriot battery in Ukraine with a Kinzhal hypersonic missile.
The Kinzhal missile was first used in combat in March against a Ukrainian position and has been used several more times during the war
While Putin and other Russian officials indicated that the Kinzhal could reach speeds of Mach 10, the NATO report indicated that it could be far slower than that.
Ukrainian Air Force Commander Mykola Oleshchuk said the Kh-47 Kinzhal had been shot down on Thursday night
A hypersonic missile is much harder to shoot down. For this reason, Israel has been increasingly worried in recent years about Iran obtaining this weapon.
Hypersonic missiles are able fly five times faster than the speed of sound and have complex and varying flight paths, making them hard to intercept.
Former President Medvedev wrote a long Telegram message criticizing the ICC for it's arrest warrant issued for President Putin.