Anita Cregan, 56, was yesterday found not guilty of aiding and abetting misconduct in a public office at Manchester Crown Court.
Police call handler Kathryn Smith, 25, and her former boyfriend Sean Booth, 31, were also found not guilty.
Ms Smith was accused of passing on information she had access to through her job to Mr Booth, who gave the information to his neighbour Mrs Cregan, the mother of his childhood friend.
Mrs Cregan's son Dale Cregan was the prime suspect for the murders of Fiona Bone, 32, who grew up in Moray, and Nicola Hughes, 23, in a firearm and grenade attack in 2012.
Cregan was jailed for life without parole last year for four murders.
He had also admitted killing father and son David and Mark Short.
Outside court, Mrs Cregan said: "I thank the jury for coming to their decision and it should never have come to court anyway.
"I feel sorry for Kathryn and Sean, they were only here because they were linked to me and my name is Cregan."
Ms Smith had told the trial that anything she discussed with Mr Booth after her shift was idle chit-chat and she trusted Booth not to pass the information on to the Cregans.