THE Hong Kong telephone prankster who has conned New York companies out of thousands of dollars is under investigation in the US. An official with the Federal Communications Commission, America's telephones regulator, said its enforcement team was looking into whether 'Dan Smith' - the mysterious recorded message artist who has tricked Wall Street brokers into making useless call for up to US$65 (about HK$502) a shot - had broken any United States laws. And he revealed the commission had recently written to Hong Kong Telecommunications Authority director-general Alex Arena expressing concern at sex lines operating out of the territory on the fee-paying '172' private lines. The commission's Brian O'Connor said of the Dan Smith scam: 'It might be a violation of the law if someone is systematically making calls and tricking people into returning the calls for the purposes of scamming people. 'It could be prosecuted by the Department of Justice, especially if tariff rates are unreasonable. We have people looking into this.' He said another option was to revoke the licence of the company carrying the service. Victims are left a message saying Dan Smith phoned and wants to be called back to discuss some business. When they call back, they are kept on hold for several minutes, running up a bill. Mr O'Connor said the commission had also written to Mr Arena about Hong Kong sex lines advertised in US magazines. Officials were concerned about minors calling the services and racking up hundreds of dollars in phone bills. He said the advertisements did not mention that the caller was dialling internationally. 'Hong Kong is one of the top 10 overseas countries for these kinds of services,' said Mr O'Connor adding that Mr Arena had written back offering his help. An Office of the Telecommunications Authority spokesman said the authority would be happy to act on complaints if more details could be sent.