AFAIK, some of it is used in the course of a crime - maybe a drug dealer on a bicycle, as an example. If they bought that bike using money obtained illegally, the PD can take it.

If the PD has officers out on bikes, it could be their surplus if they cut back, or just older bikes no longer in service.


The only way its a stolen bike going up for auction is if they don't know who the owner is or of the owner never picked it up.