Derek McLeod, 43, of Lothian and Borders Police, was jailed after being identified as the source of information.
The information was passed to the Lyons crime family.
McLeod appeared at the High Court in Edinburgh last June and admitted dealing cannabis and illegally accessing the police computer. He was jailed for two years and three months for the drugs offence and 16 months for breaching the Official Secrets Act.
Ross Monaghan was acquitted of the murder last week. A reporting ban on Mcleod was in place until the end of Mr Monaghan's trial.