Sony Music

Messy's relatives claim the opening sample, and another during the track, were taken from his videos.

They are said to be seeking $20m (£16m) in damages from Beyonce, Jay Z and Sony Music, according to US reports.

Messy, from New Orleans, was shot dead in 2010 and had spoken about young men being killed because of gang violence in his videos.

The 28-year-old singer was denied a preliminary injunction earlier this month, suffering a major setback in her bid to break her contract with Dr Luke's Kemosabe Records.

Kesha has accused the producer and record label owner of sexually abusing her - a claim he has strenuously denied.

Kemosabe Records is a subsidiary under Sony Music, so Kesha and her fans have called for the major label to take action.