Was Waingro working with the cops towards the end? Or were the cops just watching him at the hotel bc of Neil?

Harry Rollins' character, the Jim Carrey looking guy working for Van Zandt, is also an informer to Vincent Hannah's division and I think the LAPD, is the one who recruits Waingro but very little detail is given to us as to how that conveniently ties into Van Zandt's desire to protect himself from Neil and his crew. We see that brief bar scene with Waingro reaching out to a White Brotherhood guy bartending and telling him he's looking for more work and somehow this leads Waingro right into Van Zandt's arms. In the scene where Vincent and his crew take down Rollins it is mentioned that they traced the Snitch call on Neil's bank heist to the LAPD, but there's no detail on how they knew it was Rollins and for a guy who's playing both sides it seems weird that he'd slip up and get busted so easily. This is similar to the weird, if not weak, plot point about Sharlene's side-lover (played by Hank Azaria) being busted by Vincent Hannah and coerced into pin pointing Sharlene's home address when it is mentioned earlier in the movie that Vincent's team has ID'ed Chris (Kilimer). If they knew about him why did they have to do a round about and dig up Sharlene's sexcapades on the side?

I posted about this as a weak plot point, but lots of Heat STANs would have nothing of it.