has anyone noticed that crimes in countries with the death penalty are getting more and more violent as time passes by, has anyone wondered why

See "causal fallacies". It's rather more likely that the death penalty is an effect of violence -- that it's used to reduce the number of repeat violent offenders -- than a cause.

note: this is not an endorsement of the death penalty, nor a decrial of Buddhist philosophy. I simply have a pathological hatred of flawed logic used to promote one's spiritual and political agendas.