Prisoners were also offered colouring pages, Sudoku and crosswords and in some cases inmates also used adult colouring books sent to them by friends or family.
Clinical psychologist Dr Gwenda Willis told the Herald on Sunday the interest in crime and thrillers in prisons was not surprising because it reflected the reading tastes of the general population.
She said it was a positive that inmates were spending their down time in a "constructive way" by reading.
"If they are sitting reading a book then they are not going to be causing any trouble or harming anyone," she said. "I guess you could consider reading to be quite a pro social activity. There are definitely worse things they could be doing with their time."
Sudoko, crosswords and colouring-in was also a good way of engaging the mind, she said.
"For some people [colouring] can be really helpful," she said. "Those books can provide a way for people to sit down and focus on something."
