The U.S. study found that through “purposeful distortion or genuine ignorance,” hardcore criminals often co-opt religious doctrine to justify or further their crimes.

The findings could have important implications, the researchers say, for how faith-based services are administered within the corrections system.

Prison ministries shouldn’t just be about presenting religious doctrine because some inmates might take religious teachings to excuse their behaviour, lead author Volkan Topalli, a criminal justice professor at Georgia State University, said in an interview Monday.

“People have to understand that presenting religious doctrine to people isn’t enough to change their behaviour,” he said. “(Faith-based services) have to be systematic and about behaviour change — religion has to be a vehicle, rather than the goal.”

The research of Topalli and his colleagues was published this month in the journal Theoretical Criminology in an article titled With God on My Side: The Paradoxical Relationship Between Religious Belief and Criminality Among Hardcore Street Offenders.

They interviewed 48 people who were actively involved in serious and violent street-level crimes, including drug dealing, robbery, car jacking and burglary.

Almost all of them professed a belief in God and identified with the Christian faith.  However, many of the criminals had an incomplete understanding of the rules and expectations of their faith, the study found.

One 33-year-old criminal, identified in the study by the nickname “Triggerman,” refused to accept the suggestion that a consequence of murder was eternal damnation.

“No, no, no, I don’t think that is right,” he told the researchers. “Anything can be forgiven. We live in Hell now and you can do anything in Hell. … God has to forgive everyone, even if they don’t believe in him.”