More than 80 per cent of mainlanders recently detained for overstaying were forced to undergo strip-searches, according to a preliminary survey by the group's leaders. Many also endured verbal abuse from immigration officers, the survey found. 'Many of the officers had strong anti-immigrant attitudes,' said Ip Pui-yu, a supporter and volunteer survey conductor. 'They told the detainees things like: 'You people can't even speak Cantonese. You should go back to the mainland,' 'You stink, how many days has it been since you took a shower?' and 'You're wasting taxpayers' money'.' Others were forced to do squatting exercises in the nude, including a woman who previously had not spoken up about the incident, said Ms Ip. The questionnaire was drawn up by the mainlanders' lawyer Pam Baker this week after Immigration Department officials said they found no evidence of abuse following a preliminary investigation. The Correctional Services Department denied mistreating the mainlanders. The Immigration Department is in charge of the Ma Tau Wai detention centre, where 123 of the 179 mainlanders arrested after they lost a court battle last Tuesday were detained. The remaining 56 were in Victoria Prison, run by the Correctional Services Department. In a written statement yesterday, the Correctional Services Department said: 'Inquiries were made with the management of Victoria Prison about such allegations, and we were informed that none of the detainees under our custody had made, nor anyone else for that matter, complaints about being maltreated. In fact, CSD staff had got along well with the detainees during their stay at Victoria Prison.' Letters of complaint were sent by the mainlanders as a group to the two departments. But Correctional Services officials said they could not carry out any investigation without signed complaints. Mainlanders yesterday attacked the departments. 'They're being irresponsible. How could they not recognise our group complaint? If they want individual complaints, we certainly can provide that,' said mainland overstayer Penny Lam.