Your hope is in vain - they've already been exonerated, as one might expect:
Seattle Cops Exonerated After Caught On Cam Threatening To Make Up Evidence
We showed Seattle Police Sergeant Sean Whitcomb the arrest video, and he admits the 'make stuff up' comment was inappropriate. But he says the department's Office of Professional Accountability investigated the complaint and exonerated the officer.
And that’s the pity. These people have a huge amount of power. They can kill you and face less penealty than a regular person would. They need to conduct themselves better than this. His comment was disgraceful. Cops like that cause hatred of the police.