Walmart hiring criminals? (Chengdu)

There was an incident happened two years ago that one of the construction workers who managed to re innovate my apartment accidentally get hired by Walmart(成都好又多亚太店，location-No.58 Kehua North Rd Yatai Plaza,Wuhou District). He has been spreading rumours with a bunch of public apartments residents ever since,conducting criminal actions such as threatening and framing. I notified Walmart right after I found out and all my contacts who are involved(victims). I emailed to Walmart costomer servies many times seeking cooperation with the investigation as well as police officers. NO FURTHER ACTIONS IS TAKEN. I have recorded their conversation in my room which can be legal evident on court.some of the stuff workers try to cover for that suspect after i reported to counter customer services at the branch. So question is, do super giants such as Walmart allow criminals /suspects to work for them? And do chain industry lack of management?