The Serious Fraud Office (SFO) has opened a criminal investigation into the 'commercial practices' of pharmaceutical group GlaxoSmithKline (GSK).The UK fraud body called on whistleblowers to come forward with any information. "We welcome approaches from anyone with inside information on all our cases including this one," it said.While details regarding this particular case are not yet known, the news will come as a further blow to shareholders after a wave of allegations against the company relating to international bribery.Police at the Ministry of Public Security in China earlier this month accused GSK of earnings billions of yuan illegally through "massive and systemic bribery". Individuals at the company's Chinese subsidiary were alleged to have funnelled money to hospitals, doctors and government officials in recent years, paying for bribes by hiking the price of medicines, according to reports.The pharma group is also said to be facing similar investigations in Poland and Iraq.GSK confirmed the SFO inquiry in a statement on Tuesday, saying: "GSK is committed to operating its business to the highest ethical standards and will continue to cooperate fully with the SFO."BC