Ping
If the pistol was taken for PM this may think that is one of Izh (Baikal) produced pistols of this design for different ammo and purpose.
Like:
1. Tear-gas pistol Izh-79
2. Rubber bullet version , fires also tear gas ammo Izh-79-9Ò
3. A version for security agencies, fires weaker 0.380ACP
4. Export-only Baikal-442
As anyone can see, the 4 version can be mixed up easily.
Silencer is more proof that this was an FSB hit job.