A former detective constable and three people have been convicted of smuggling contraband into prisons using drones.
Police said drones containing prohibited items were flown into HMP Onley in Northamptonshire and HMP Gartree in Leicestershire throughout 2021 and 2022.
At Coventry Crown Court, former Staffordshire Police Det Con Clare Davenport, Peter King, Kent George and Mervyn Foster were convicted of being involved in the enterprise.
All four people are due to be sentenced on 17 November.
The force said packages inside the drones contained Class A and B drugs, alongside tobacco, mobile phones and other contraband.
One package, which was recovered by a prison officer in August 2021, contained heroin with a prison value of £22,400 and cannabis worth £15,300.
King pleaded guilty in August to conspiring to bring, throw, and or convey List A and List B prohibited articles into or out of prison, and conspiring to acquire, use or possess criminal property.
Davenport, 50, pleaded guilty in August to the same offences.
George, 63, and Foster, 45, were found guilty of the same offences after a trial which concluded on Monday.
Det Insp Carrie Powers, from the serious and organised crime team said: “This was a very complex investigation involving a number of agencies and I am really pleased that not only did we stop these drone drops from happening, but that the people responsible have been brought to justice.”
A gross misconduct hearing held by Staffordshire Police on 3 August 2023 had concluded that Davenport would have been dismissed if she had not already retired.
