The Catholic nun who inspired the movie “Dead Man Walking” is in Iowa today to spread her message against the death penalty. Sister Helen Prejean says for all the talk about the death penalty, Americans seem to know little about it.Prejean says she tries to dispel ideas about the death penalty fostered by political rhetoric. She says the death penalty is very selective as only one to two percent of the people who committ murders are sentenced to death. Prejean says those who’re put to death are overwhelming black.She says she also tries to point out how flawed the system is in determining guilt, as 87 innocent people have come off death row since the death penalty was made legal again.Prejean says people who are locked up for committing a murder rarely get out of prison. She admits part of the solution is changing a society that has fostered so much murder and crime.Prejean says one person can make a difference and Americans can’t afford to stand back and do nothing if society is to change.Prejean will speak at a Catholic Peace Ministry event tonight in Des Moines.