In possession of 'that' information, the relatives eventually gained the upper hand over Essex police, and were able to manipulate them to do what they wanted otherwise the relatives themselves would 'spill the beans'...
The 'hold' which the relatives gained over the investigating officers, was a similar one which professional informants eventually have over the cops they have 'grassed' to, or to whom they give information to in return for cash and favours. The power these informants have is that at any time they can come forward and effectively help to get many convictions quashed simply by saying that 'cops put me up to this, they told me to help them put this person away, or that person away. I personally know the identities of several paid police informants who acted in this capacity against me for the No.3 Regional Crime Squad, and South Yorkshire police when I was considered to be a target Criminal (Gordon Stanton, Graham Thompson, Harold Hawksworth, and Godfrey Lewis, to name but a few). I even have a transcript of when the cops interviewed Thompson whilst he was in prison, making a deal to get himself released on bail at the expense of being encouraged to 'tell cops lies about me'...
Gordon Stanton's wife, 'Debbie', even made covert taped recordings of her husband admitting that he was working for the No.3 RCS, to help convict me, and that they had paid him two payments already, one of £15,000 and the other of £10,000....
In a similar sort of a way, the relatives had the 'bargaining power' of PC Robert Carr, he was their 'informant'...