The family of late rapper Drakeo the Ruler has filed a wrongful death lawsuit against Live Nation, citing a lack of “proper safety measures” at the Once Upon a Time in LA festival on Dec. 18.

The 28-year-old rapper was fatally stabbed backstage at the festival, before he was scheduled to perform. The court documents obtained by Variety, which were filed on Wednesday on behalf of Drakeo’s 5-year-old son, allege that his death was “at the hand of a violent mob of purported members of a Los Angeles based Bloods gang.” The stabbing, the filing claims, was the “result of a complete and abject failure of all Defendants to implement proper safety measures in order to ensure the safety and well being of the artists whom they invited and hired to their music festival.”

In addition to Live Nation, the suit is also filed against the festival’s co-promoters — Bobby Dee Presents Inc., C3 Presents and Jeff Shuman — in addition to the Los Angeles Football Club, which subleases the stadium where the festival took place.

In response to the suit, a Live Nation rep offered the following statement on behalf of the festival organizers: “Once Upon a Time in LA joins Drakeo’s family, friends, and fans in grieving his loss. The festival is continuing to support local authorities in their investigation as they pursue the facts.”

The lawsuit continues: “Had Defendants and each of them, placed the safety and wellbeing of its guests and its invited artists ahead of profits, there would have been an adequate security plan and sufficient security guards and law enforcement presence to have prevented the unnecessary and untimely murder of Drakeo The Ruler, at the hands of over 100 deadly gang members who inexplicably gained access to a restricted area of the venue engaging in an unrelenting and unprevented attack for over 10 minutes.”

Representatives for C3 Presents, Shuman and the LAFC did not immediately respond to Variety‘s request for comment. Bobby Dee Presents had no comment.