Does Putin's regime have a habit of targeting families of its opponents?
Occassionally videos, pictures or other identifying information of Russian soldiers who surrendered or defection to Ukrainian forces pop up on social media. While there are various ethical concerns about this, a particular point gets frequently made: That this would put family members of the identified Russian soldier who are living in Russia in significant danger.
But do we have any actual cases of Putin's regime exacting revenge on family members of its opponents (whether its dissidents, defectors, etc)? I would count only very severe acts (murder*, torture, prolonged incarceration), not eg police harrassment or losing a job.
An ideal answer would point to a quality external source answering the question. But listing examples of proven or suspect cases; or explaining why a lack of known examples is or is not good evidence to conclude that it happens at most very rarely, would also be appreciated.
(*) Collateral damage in an attack on the opponent themselves doesn't count.