GlaxoSmithKline (NYSE:GSK) is reportedly investigating further allegations of bribery from an anonymous tipster, who says that sales staff would pay doctors with cash and perks for prescribing botox and that they would use private email accounts, as opposed to their GSK addresses, to cover their tracks. GSK said it has so far found no evidence of bribery or corruption connected to botox; the company, some of whose Chinese staff were recently arrested for economic crimes, said the same thing last month about similar claims from the tipster.