Operation Alice officers were tasked with investigating who passed information to The Sun and The Telegraph newspaper regarding the "Plebgate" incident, including whether the leak came from within the police force or from a third party.
They examined a police witness statement from the incident and investigated if there was a conspiracy between the officer and another party.
They also investigated claims made by Andrew Mitchell that police lied in the police log of the incident.
More top news
Comcast said its cash offer is worth £12.50 a share – a 16% hike on the £10.75 a share offered by 21st Century Fox.
The Duke of Cambridge said the new prince was "behaving himself" and sleep was "going reasonably well so far".
The challenge came as Theresa May vowed no stone would be left unturned in putting right the status of the Windrush generation.