D- neighborhood dilemma [THIS POST IS GROSS]

[Miho Y.]

So my rental in LA is extremely rough area. I have this ideal tenant who is very stable with job and his family moved in last year. They reported to me that there's someone moved into the garage across the alley. Such a tenant drinks beer at the corner of the alley which is ON MY PROPERTY that belongs to my nice tenant. Then leaves the empty beer bottles on top of the concrete enclosure which belongs to my nice tenant. The garage this drunkard/drug addict is not a dwelling meaning there's no bathroom. This tenant goes both #1 & #2 shamelessly on the alley in front of my nice tenant's garage, and of course, don't clean afterwards. My nice tenants are afraid of confrontation especially I think is because they have a very pretty teenage daughter. My fear is that they'll leave. Any suggestion/recommendation would be appreciated as to how I, as a property manager, can approach this situation without none of us getting killed. Should I report to Police? But that police station is too busy to handle public defecation.