Here's the deal ... thanks to a hella popular Netflix series and doc ... people have been swarming the affluent Beverly Hills location where Lyle and Erik Menendez brutally murdered their parents in '89 ... the duo later claimed it was a response to the severe lifelong abuse they endured.

Police tell TMZ ... what were initially calls from pissed neighbors about an uptick in foot and car traffic  -- annoying, but not illegal -- have now escalated to straight-up trespassing ... and in one case, an apparent break-in caught on TikTok.

Now ... police are worried it's going to spiral into a bigger clusterf*** with Halloween right around the corner ... so discussions are underway about how best to ward off any idiots seeking a spooky thrill.

For the moment … the house is empty as it undergoes major renovations … which has no doubt led to the brazen sightseers. It's also definitely not helping that some Hollywood tour buses (but not TMZ!) have added the block to their route ... unloading groups of people on the area.

Police have already stepped up patrols in the area to chill out irate residents ... but we're told more needs to be done as Halloween gets closer... maybe even private security, which is being recommended to property owners.

TMZ previously reported ... Menendez Brothers-inspired costumes have become a hot-ticket item this season ... so it's not far-fetched to assume someone out there might be looking to get a creepy snap on location.