I really find them either overworked and understaffed or terrified of finding against bent cops. One of the many flaws in police behaviour in 2015 to 2018 was failure to properly investigate anything proving my innocence; one witness proving a man was lying when he said he lost his virginity around his 14th birthday (he claims she saw a birthday card in his house - he'd pretended to be 15) "could not be found" after weeks of "searching". We found her in 5 minutes and her evidence was absolutely 100% solid against his deliberate lies. She'd never been to his house, never seen any birthday card and, indeed, they had lost both their virginities together just weeks before both their 16th birthdays.