Ofcom has launched an investigation to explore whether Sky News' 2008 decision to hack the email account of a man later found guilty of fraud was done in the public interest.
The UK regulator confirmed the investigation in a statement sent to V3 on Monday.
"All we can do at this stage is confirm that we have launched an investigation into the fairness and privacy issues raised by Sky News' statement that it had accessed without prior authorisation private email accounts during the course of its news investigations," said the spokesman.
The investigation follows on from Sky News' admission that it had hacked into the email accounts of John Darwin.
The hack led to the revelation that Darwin had faked his own death so that his wife could claim his life insurance money and pensions.
Speaking to V3, a Sky News spokeswoman reiterated the broadcaster's insistence that it had behaved appropriately.
"As the head of Sky News, John Ryley, said earlier this month, we stand by these actions as editorially justified. The Crown Prosecution Service acknowledges that there are rare occasions where it is justified for a journalist to commit an offence in the public interest," said the spokeswoman.
The revelation has since cast further doubt on the news outlet's ethics policies. Prior to the discovery, the Rupert Murdoch-owned News of the World newspaper had similarly been caught hacking phones to generate stories.