lIn July last year, a gang of four had raided three houses in Salt Lake and raped a 15-year-old in front of her parents.

lA few months later, a mobile phone theft racket was busted and the main players were picked up from an unauthorised shanty in Salt Lake?s Duttabad area.

The spurt in crime that the showpiece township witnessed a few months ago has been curbed to some extent. But the authorities fear the situation may again worsen if the problems of illegal shanties and unlicenced autorickshaws are not addressed immediately.

?The illegal shanties ? there are thousands of them across the township ? are the perfect hideout for criminals. We have requested the municipality to evict the settlers,? a senior officer of North 24-Parganas police said on Thursday.

According to him, local criminals as well as those from outside (the serial dacoity and the rape were committed by criminals from South 24-Parganas) take shelter in these unauthorised settlements.

?It is difficult for someone to carry arms into the township at night or early morning, as the vigil is very tight then. But not so during the day. We have information that criminals often use the shanties to hide their arms for use at night,? the officer pointed out.

?The shanties are, indeed, a big problem,? admitted an official of Bidhannagar Municipality. ?We had undertaken several eviction drives, but the settlements always reappear.?

Most of those living in the illegal structures run food kiosks, pan-cigarette stalls, grocery shops and laundries. According to a police estimate, there are at least two makeshift laundries in each block.

?Vacant plots are our constant source of worry, as they invite encroachers,? the official said. Although urban development rules bar an owner from keeping his plot vacant for more than three years, several plots are lying unused for more than a decade.

Law and order in Salt Lake is a primary concern of the government, as the township is in the focus of the ongoing information technology drive.

?Salt Lake is the government?s IT showcase. Any negative development there will send wrong signals to investors and clients,? said an official in the IT department.

Illegal autorickshaws are another headache for the police. ?The drivers often have links with criminals and act as go-betweens, especially in cases of mobile phone thefts,? an officer said. An estimated 500 autorickshaws ply in Salt Lake, several of which do not have permits.