A Texas death row inmate has become an internet sensation after comparing the US justice system to slavery in his final letter before execution.

Ray Jasper, who is due to be executed this month for taking part in the killing of studio owner David Alejandro in 1998, sent a letter to Manhattan media news site Gawker.com.

Jasper - who had already once written to Gawker, following the initiative "Letters from the Death Row" launched by the website - said he considered the second letter to senior writer Hamilton Nolan as his possible "final statement on earth."

Jasper reflected on the American justice system, which he defined as being "truly broken beyond repair", adding: "Martin Luther King said a revolution comes by social action and legal action working hand in hand. I'm not presenting any radical revolutionary view, the word revolution just means change. America changes as the law changes."

He went on to say: "We look at slavery like it's a thing of the past, but you can go to any penitentiary in this nation and you will see slavery.

"If a prisoner refuses to work and be a slave, they will do their time in isolation as a punishment. You have thousands of people with a lot of prison time that have no choice but to make money for the government or live in isolation.

"The other side of the coin is there are those in the corporate world making money off prisoners, so the longer they're in prison, the more money is being made. It's not about crime & punishment, it's about crime & profit."

On capital punishment Jasper commented: "I don't agree with the death penalty. It's a very Southern practice from that old lynching mentality. Almost all executions take place in the South with a few exceptions here and there. Texas is the leading State by far.

"The lethal injection has become a real controversial issue here of late because states are using drugs that they're not authorised to use to execute people. The lethal injection is an old Nazi practice deriving from the Jewish Holocaust. To use that method to kill people today, when it's unconstitutional to use it on dogs, is saying something very cruel and inhumane."

Jasper also commented on the criminal law in Texas, which he defined as a "very 'country' state, aside a few major cities. There are still small towns that a black person would not be welcomed.

"Capital murder is if you take someone's life and commit another felony at the same time. That's Texas law. That makes a person eligible for the death penalty.

"The problem is, you're not getting the death penalty for murder, you're actually getting it for the other felony. That doesn't make common sense.

"The last thing on my heart is about religion and the death penalty. There are several well-known preachers in Texas and across the South that teach their congregations that the death penalty is right by God and backed by the Bible. The death penalty is a governmental issue not a spiritual issue."

In the last few lines of his letter, Jasper challenged any preacher in Texas to "come visit me and tell me that God wants me to die.

"Again, Mr. Nolan, this is only my perspective. A doctor can't look at a person and see cancer, they have to look beyond the surface. When you look at the Justice system, the Death Penalty, or anything else, it takes one to go beyond the surface. Proper diagnosis is half the cure."

During his trial in 1999 Jasper pleaded not guilty, claiming he "knew David". He will be executed on 19 March 2014.

You can read the full letter here.