Death penalty pros and cons
There is a chance they can return to society. Prisons and the judicial system are not perfect. Extremely violent offenders can still return to normal society to wreak havoc through escape, pardons, changes in laws and regulations. To prevent this danger to society a permanent solution would be better.
Imprisonment can be a form of cruel and unusual punishment. The many problems plaguing the prison system has lead to an uncivilised environment within the walls. Rape and torture are some of the many things that occur in prison due to overcrowding and highly violent offenders receiving life sentences instead of death sentences. Death can be a humane punishment.
It is not a deterrent. Statistics will show quite clearly that places implementing the death penalty have shown no reduction in the crime rates related to that sentencing. Most violent criminals are not concerned with consequences and if they are they would view life in prison as no different from execution.
Declutters prisons. Allowing inmates to waste away in prison is a drain on the economy and a burden on society. The prison system in most countries is rife with problems and issues and this will be solved by reducing the influx of inmates with life sentences.
More resources than alternative sentencing. Despite the common misconception the death penalty costs the economy more money than the imprisonment of an inmate. Statistics and data of areas with the death penalty vs those without show this clearly. When an inmate is sentenced to death it takes years before the sentence is carried out.