Whitney Houston's family reportedly "ordered their security" to move Ray J away from them at the Billboard Music Awards on Sunday.
The 31-year-old R&B singer dated the iconic star on and off for several years and spent time with her in the days before her death on February 11. Ray has been blamed for contributing to Whitney's demise by some of those close to her.
According to US website TMZ, the Houston family - including Whitney's daughter Bobbi Kristina and sister-in-law Patricia - were angered when they learnt they were seated close to Ray at the prestigious music event.
Patricia reportedly "ordered their security to get him away from them" but the star "refused to budge". Other insiders added that Patricia's security detail "summoned hotel security, along with several uniformed officers to physically remove Ray J."
Ray allegedly said to friends at the event: "Pat ruined what was a great opportunity to honour the woman who I loved."
The Billboard Music Awards paid tribute to Whitney, with Jordin Sparks performing her hit I Will Always Love You. Bobbi Kristina was seen breaking down in tears in the audience and later took to the stage to accept the Millennium Award on behalf of her mother with Patricia.
