Sky News has admitted it hacked email accounts belonging to members of the public, but has defended its actions as "responsible journalism", the BBC reports.
The hacking victims include John Darwin, who faked his death in a canoe, and his wife Anne, as well as a suspected paedophile and his partner.
In a statement Sky News said that it was "acutely aware of the tensions that can arise between the law and responsible investigative journalism.
"We stand by these actions as editorially justified and in the public interest."
The broadcaster said the evidence it discovered was handed to police and used in the successful prosecution of Darwin's wife Anne for insurance and pension fraud.
Darwin, 61, faked his own death in a canoeing accident in 2002 so his wife, 60, could claim hundreds of thousands of pounds from insurance policies and pension schemes.
Former Sky News managing editor Simon Cole agreed that North of England correspondent Gerard Tubb could hack into Darwin's Yahoo! email account.
Mr Tubb uncovered messages which cast doubt on Mrs Darwin's claim during her criminal trial that her "domineering" husband forced her to go through with the fraud plan.
The Darwins, from Seaton Carew, near Hartlepool, were jailed at Teesside Crown Court in 2008 for the swindle, which deceived the police, a coroner, financial institutions and even their sons Mark and Anthony.
Adding that it did not " take such decisions lightly or frequently" the company described its actions as built upon "finely balanced judgement."
Sky stressed that any decision must be "based on individual circumstances and must always be subjected to the proper editorial controls."
In a separate case, Mr Tubb was authorised to access the emails of a suspected paedophile and his wife, although this investigation did not result in any material being published or broadcast.
Cleveland Police said in a statement: "Cleveland Police has conducted an initial review into these matters and can confirm that inquiries are ongoing into how the emails were obtained."