New Delhi ( CNN ) A gang of robbers struck a Christian school in eastern India on Saturday , and one of them raped a 71-year-old nun , a senior official said . The man apparently did so , because she resisted the robbers , said P.B . Salim , chief administrator of the West Bengal state 's Nadia district . Previously , a church official had told CNN sister broadcaster CNN-IBN that three or four of the men had raped the woman . A group of seven to eight men allegedly barged into the school and its attached staff residence during pre-dawn hours , and the elderly Sister Superior raised an alarm and resisted , Salim said . The rape was apparently punishment for it . Later , the men tied her up along with two other nuns and the building guard . The robbers then made off with cash worth a few hundred thousand rupees ( thousands of dollars ) , laptops and other articles , Salim said . The attacked nun is under medical care . `` Physically , she is better . But the mental trauma will take its own time to heal , '' Salim said . `` It is a very , very shameful act , first of all , to rape any woman , any female , '' Father Dominic Emmanuel of the Delhi Catholic Archdiocese said in televised comments . `` But this one becomes even worse because , first of all , she is an old lady and then on top of it , she is a nun . She is a religious ( and ) has consecrated her life to God and all her life she has remained a virgin . '' The investigation into the burglary and rape is ongoing , and no arrests have yet been made , Salim told CNN . A series of rape cases involving girls , foreign tourists and a physiology student who died following a brutal gang rape in 2012 has hurt India 's international reputation . Crowds have taken to Indian streets to protest against rape . The nation 's lawmakers introduced tougher laws and punishments for sexual crimes and harassment . Despite such action , India continues to see episodes of sexual violence . For instance , five men were arrested in Kolkata in January and charged with raping a Japanese tourist . Police said the men operated as a gang and targeted single , Japanese tourists . In December , an Uber driver was charged with sexually assaulting a passenger . The incident that grabbed the world 's attention was the rape of a woman by five men on a bus in 2012 . She later died of her injuries . Anti-rape activists complained when the Indian government restricted the showing of a BBC documentary about rape that included comments from one of those men . He provoked outrage around the world by blaming the victim and saying the woman `` should just be silent and allow the rape . '' Official data in India show that rape cases have jumped almost 875 % over the past 40 years -- from 2,487 in 1971 to 24,206 in 2011 . But campaigners say sexual assaults are underreported because of stigma and cultural factors . Experts say the causes of the high number of rapes include the nation 's patriarchy , widespread poverty and lack of law enforcement in rural areas .
Official says men broke into a convent school and one sexually assaulted a septuagenarian nun . A series of publicized rapes have occurred in Nadia in recent years .