Immigration officers were accused last night of being prejudiced and insensitive in a blunder that led to a mentally disabled boy being wrongly sent over the border to Shenzhen. The desperate search for Yu Man-hon, 15, continued last night in Shenzhen, six days after he was turned out on to the streets alone. The autistic boy, who has a mental age of two, was released unaccompanied on the Chinese side of the border last Thursday. He cannot speak and he has no money. Anger mounted last night as local parents' groups and human rights activists said it was 'inhumane' for officials to send Man-hon out on his own, apparently unaware the boy could not take care of himself. A spokesman for the Immigration Department said it had kept in touch with Shenzhen public security officers in the search for Man-hon. The department's Assistance to Hong Kong Residents Unit has contacted the boy's parents to offer help. The spokesman said: 'The department has commenced an investigation to dig out more facts of the case.' Chairwoman of the Equal Opportunities Commission Anna Wu Hung-yuk said the immigration officers had shown prejudice against people with disabilities. 'It is discrimination in a sense that it involves assuming this person is difficult, assuming he is an illegal immigrant, while he is in fact a Hong Kong person. Discrimination arose from ignorance regarding the mental condition of the person. There is nothing more important for immigration officers than to safeguard the right of a person to remain in Hong Kong. When you make a wrong assumption it can lead to consequences that are devastating. 'The attitude seems to be insensitive and certainly unfair. It is tragic to the individuals and may be discriminatory.' The Security Bureau said it would review the present operation to see if any improvement was needed, adding that the case was rare. Man-hon, who lives in Wong Tai Sin, ran away from his mother at Yau Ma Tei MTR station at 11am last Thursday and was spotted by mainland officials on the Shenzhen side of the border later that day. He was sent to the SAR side to confirm his identity. It is not known how he got through immigration controls. SAR immigration officers said they could not confirm he was a Hong Kong resident during a two-hour interview because he did not respond to questions. Man-hon was sent back to Shenzhen at 7pm the same day and freed to wander the streets. No medical advice was called for when Man-hon became highly emotional during the interview. He urinated, spat and also threw food and water at an officer. An Immigration spokesman said officers had never suspected the boy had mental problems. The Equal Opportunities Commission will soon contact the department to offer a sensitisation programme for officers. Castle Peak Hospital psychiatrist Dr Tsang Fan-kwong said: 'Someone should have the sensitivity to suspect a child, who shows emotional and speech problems, may have some health problems.' Paula Scully, chairwoman of the Guardianship Board for people with mental disorders or disabilities, said the officers should have sought medical advice. Human Rights Commission chairman Ho Hei-wah called on Chief Executive Tung Chee-hwa to seek help from Guangdong's Public Security Bureau.