There is a common belief that it’s inevitable that prisons will be dangerous places, since they are filled with dangerous people.

Nothing, however, is further from the truth. Prisoners, who have no freedom of movement or right to privacy, aren’t able to conceal weapons and commit crimes as they did when they were on the street, no matter how lawless they used to be. As a result, prisons should be one of the safest places in our society.

That’s not always the case, however, as events last week at the Maine State Prison showed. Inmate Richard Stahursky allegedly hogtied inmate Micah Boland and stabbed him 87 times. This took place during a meal time when cell doors were unlocked, and prisoners and corrections officers were moving around the facility.

The prison administration is conducting and investigation, as it should. While Stahursky allegedly has taken responsibility for this murder, telling authorities “I get stupid sometimes when I have a knife in my hand,” prison officials should take a careful look at the practices and procedures that allowed this crime to happen.

Some members of the public may see a form of rough justice in this killing. They may think that Boland, who was serving a 22-year sentence for molesting a child, got what was coming to him. That attitude, however, is damaging to all of us.

Criminals are sent to prison to remove them from society — that is their punishment. Letting inmates create their own punitive system in which the strong prey on the weak is not justice.

And treating prison violence as someone else’s problem is very short sighted. Almost all inmates will someday return to the community. How many lessons in cruelty and indifference do we want them to have before they do?

No one likes crime, but as a society we understand that a certain amount of crime is the price we pay to enjoy our freedom to live without government surveillance.

Prisoners don’t have that freedom, so, paradoxically, we should be less tolerant of crime behind bars than we are of crime on the street.

Prison authorities should get to the bottom of this crime, finding out not just who wielded the knife, but also how the murder was allowed to happen in such a controlled environment.

The rest of us should never accept the notion that prisons should be dangerous places. We should, instead, demand that all inmates be able to serve their sentences in safety.