Can you please direct me to a list of Putin's victims?

Everyone blithesly asserts that Putin has people killed, but I have never seen a single credible case made. It always starts out with headlines touting MI6 and/or CIA having "high confidence" that the Russians have assassinated someone, but then the story fades and no actual proof is ever introduced. Examples are the Skripals and Navalny - no there there in either case.