Johannesburg - Mayor of Johannesburg Herman Mashaba has called on whistleblowers with information on the illegal sale of RDP houses to come forward after the arrest of a volunteer alleged to have sold three properties in shady deals which failed to materialise.The volunteer, who worked at the City of Johannesburg’s Ivory Park Housing Department offices, was arrested by the Hawks on Friday for illegally selling council stands and RDP houses.The arrest came after a complaint was received from a buyer who purchased two RDP houses for R150 000 in Ivory Park, north of Johannesburg, Mashaba said in a statement.He explained that the woman had told the complainant in September 2014 that she had two available houses for sale which was occupied by illegal immigrants. Each house was sold for R75 000.The money was paid at the end of that year, but the buyer never received the keys to the homes."Upon learning that she was scammed by the suspect, the complainant in August 2016 reported the matter to the suspect’s manager. The suspect then promised to pay back all monies that were paid to her but never did."It is also alleged that other officials from Ivory Park’s Housing Department are also involved in the scam. The allegations are being investigated."The woman is suspected to have scammed other people in the area, Mashaba said."In 2012, the suspect illegally sold a vacant stand to a member of the public for R65 000. Only R55 000 was paid into her account and the second complainant promised to pay the balance upon occupation. A lease agreement between the two was signed but the second complainant never occupied the stand."The suspect told the second complainant that there were people who were illegally occupying the stand and would be evicted. In 2014, the second complainant asked for his refund but he never received it and was told that the suspect is no longer working for the city as a volunteer."Mashaba appealed to anyone with information on similar scams to send a tip off to the city so that it could be investigated by its law enforcement agencies.