A FURTHER 18 people have been arrested over the continuing investigation into the construction of 30,000 illegal homes in Chiclana.As well as builders, valuers and estate agents, investigators believe that various bank workers may also be involved. The arrests revolve around a series of false documents purporting to show properties were older than they were in reality.The certificates were then used to obtain mortgages from the banks who may have been in collusion. The arrests bring the number of arrested so far to 57 people in the town, which has become one of the worst black spots for illegal building in Andalucia.It is estimated that between 2005 and 2007 there was practically no town planning discipline by the council. The current investigation at Chiclana's Court number 2 has seen 18 people charged with fraud, falsifying documents and breaking land laws. In particular the claims centre around the area of Canteruelas Viejas, where in 2005 an aerial photo shows that there was only one building standing. However in 2007, hundreds of new home owners insisted that their homes should be legalised as they had been standing for at least five years.The police investigation is also now looking to see how closely the banks may have been involved.The Olive Press reported in June how some 200 Britons had unwittingly bought illegal houses. A local expat association, the Chiclana Foreign Residents Association was set up to tackle the problem.Chairman Colin Wood said: "Like many people we went through the proper channels to buy our property. We used an estate agent, a lawyer and a notary - even the bank we got our mortgage from looked over the paperwork and everyone said it was OK. "We fell for it hook, line and sinker."The town hall is currently trying to legalise around 15,000 of the illegal properties.Meanwhile Barbate town hall is hoping to legalise around 500 illegal houses in the Zahora area near the Trafalgar lighthouse.The authorities want to make the area, currently designated as non development land, into a legal urban area.