Should the death penalty be done away with? Their has been mistakes by our justice system and poor defense council yet their others who did murders and admitted to it what is the answer?

Yes but if convicted of murder they should get life with no parole. Many murderers repeat it when released..,plus they have the rest of their lives to prove innocence 

The alternative is to support murdering scumbags on taxpayer dime for the rest of their miserable lives. If the death penalty is abolished, jail sentences for marijuana "crimes" should be abolished to free up jail cells for the murderers.

Gandalf gave the definitive answer. He said, "Some live who should have died; but others died who should have lived. Are you wise enough to know the difference?"

The classic case was one in which the FBI framed four men for murder to protect an informant. Two of them died in prison, the other two spent forty years behind bars before they were exonerated and paid over $100 million in compensation. Had the death penalty been mandatory they would have been executed. US must pay $101.7 million compensation.

In 2013 the ten countries who executed the most people were, in order: 
China
Iran
Iraq
Saudi Arabia
North Korea
USA
Somalia
Sudan
Yemen
Japan.
Surely Americans must feel uncomfortable about keeping such company. Death Penalty Statistics: Country by Country.

I believe that the investigation shouldn't stop when the suspect admits the crime because there might be other things happening w/o the knowledge of the jury and judge. 

We don't have the death penalty here anymore. And I can tell you we would actually rather have it back.

But there will always be the moral dilemma attached to both sides