Prison visitors arrested in drugs operation at Shropshire's Stoke Heath prison
Arrests were made as part of a police operation to tackle drug smuggling into Shropshire's only prison.
Checks were carried out on people visiting prisoners at Stoke Heath Prison, near Market Drayton.
Those carrying out inspections aimed to prevent prison-related drug offences.
The operation, which happened last week, was carried out by officers from the prison, police and officers from the National Crime Agency.
Police said one woman was found in possession of heroin. She was released under investigation.
Another woman was found in possession of a small amount of cannabis and given a caution.
A third woman was found in possession of cocaine and cannabis. She was also released under investigation.
One man was found in possession of cannabis in a car. He was released and no further action was taken after interview.
Constable Mick Sturland, of the Market Drayton Safer Neighbourhood Team, said: "This operation was a success but does highlight the issue of drugs being bought into prison.
"Together with prison management and colleagues from other enforcement agencies, we will continue the drive to identify those responsible for bringing illegal substances into the prison."
Westwood, 40, took a package containing cannabis and anabolic steroids to the prison last year.
It was passed to Osbourne Walton, an inmate at HMP Stoke Heath, who she did not know and had only spoken to on the phone.
Westwood, of Leyland, Lancashire, was found guilty of three charges of taking prohibited material into a prison following a two-day trial.
It comes after last year police said that mobile phones and contraband were being thrown over the prison walls at Stoke Heath, prompting extra patrols.
It is a criminal offence for an inmate to be in possession of a mobile phone and offenders could be handed a two-year jail term on top of their sentence.