IT companies in Bangalore, including Infosys Technologies and Wipro, received an e-mail last week threatening to blow up their facilities, according to police officials. The e-mail was addressed to six companies in Bangalore, said Bangalore's Joint Commissioner of Police, Gopal B. Hosur, on Monday. The mail was sent from a location in Bangalore, and police are working on tracking the sender, he said. Infosys has received a threatening e-mail, also addressed to various other companies, said a spokeswoman for the company. Local authorities have been contacted and are investigating, while security continues to be on alert in all Infosys campuses, she added. Wipro declined to comment on the e-mail threat. Indian IT companies and IT subsidiaries of multinational companies have been terrorist targets for some years now, as they have come to represent India's economic boom, according to the police. But there have been no attacks yet on IT companies in India. In the case of the e-mail threat too, sources close to the situation suspect that the e-mail may have come from a prankster.Security has already been tightened at IT companies in Bangalore after the attacks in Mumbai, India's business hub, in November, Hosur said. The police will be extending all help to IT companies in Bangalore in view of the e-mail threat, he added.