More than 450 victims of the Oct. 1 massacre in Las Vegas have filed a lawsuit in California against MGM Resorts International and other defendants...The lawsuit includes two wrongful death claims, while lawyers involved in the litigation also have filed other complaints in Los Angeles...Among five complaints filed...in Los Angeles Superior Court, one names hundreds of victims from Nevada, California and 19 other states, along with victims from Canada.  Alleging negligence, the suit claims that MGM...failed to properly monitor the people entering and leaving the Mandalay Bay suite from which shooter Stephen Paddock fired upon a crowd of thousands at the Route 91 Harvest festival, killing 58 and leaving more than 500 injured.  Along with the hotel-casino giant and Paddock’s estate, defendants include MGM Resorts Festival Grounds LLC, Live Nation Entertainment Inc. and Contemporary Services Corp., a security company...According to the suit, MGM acted negligently in several ways: failing to monitor the hotel premises..., failing to respond to the shooting of security officer Jesus Campos, failing to notice or take precautions against Paddock’s delivery of guns and ammunition to his hotel room, failing to adequately prevent or discover broken windows; failing to train employees on suspicious activity, and ignoring the “do not disturb” sign...