KOLKATA: The city sessions court on Tuesday held a Bangladeshi national guilty for the March 2015 rape of a 71-year-old nun of a convent in Ranaghat , more than 80km from here. Nazrul Islam alias Noju was also convicted for robbery and criminal conspiracy with four others and a sixth person was held guilty of harbouring them. The court will read out the sentence for all six guilty on Wednesday, with the rapist looking at spending the rest of his life in jail.Judge Kumkum Sinha, while pronouncing the verdict, termed the incident as a blot on a state where Sister Nivedita and Mother Teresa had worked for people. "What happened to a senior nun here is a blot on Bengal 's legacy," she observed before reading out the verdict."Your results will be out today, you must have had a sleepless night," she said, directly addressing the six, using the metaphor of the venue — a school — where the crime was committed. The judge switched to Bengali to ensure the six understood the enormity of their guilt and the verdict.The six forced their way into the convent school in the early hours of March 14, 2015, after overpowering the guard at gunpoint. They then climbed to the first floor and took whatever valuables they could find. Islam locked the 71-year-old nun in a room and raped her when she tried to resist the looting. The brutality of the assault was such that she had to undergo a surgery.Several arrests were made one after the other from March 26 to June 17, when prime accused Noju was finally arrested from Sealdah station as he was getting off a local train.