Police are warning residents about vacant foreclosed homes which they say are inviting criminal activity.    Officer Mike Lopez with the Los Angeles Police Department says criminals are taking advantage of landlord-tenant laws by refusing to leave, essentially “squatting” until they’re forced out. “They’re establishing residency there and it’s hard for us to have them legally evicted because they’re showing proof that they’re living there,” Lopez said. The LAPD says it’s happening in neighborhoods all over Los Angeles with criminals fully aware that the eviction process can take between three to six months.