Twenty-two prisoners were injured, one of them grievously, after a wall of a barrack in Bhind district jail of Madhya Pradesh collapsed early on Saturday, an official said. The wall of barrack number 6 caved in around 5.10 am, Bhind Superintendent of Police Manoj Kumar Singh told PTI over phone. The police officer said that the jail building was quite old and the wall might have collapsed as a result of incessant rains over the last couple of days.