Just weeks after prosecutors successfully increased the murder sentence of Oscar Pistorius to 13 years and five months, the former Paralympic gold medalist and Olympics sprinter has been injured in a prison brawl, according to the BBC.

The disgraced Paralympian was allegedly involved in a fight over the use of a public phone, a prison department spokesman told the BBC. Pistorius ... sustained a bruise, he added.

The brawl, which the BBC said took place on Dec. 6, occurred at Attridgeville Correctional Centre, where the six-time Paralympic medalist is serving time for killing his girlfriend, Reeva Steenkamp. It has since spawned an investigation, the report added, "to establish the facts and to ensure that appropriate action is taken as incidents of assaults are not allowed."

The London Evening Standard, citing an unnamed source, suggests that "fellow inmates became incensed" when Pistorius "refused to hang up" during scheduled time at the prison phone.

Originally sentenced to five years in prison after the murder of Steenkamp, Pistorius has since seen his prison time escalate on two occasions -- first to six years and then, in November, after appeals from prosecutors, to more than 13. An international story when he became the first double leg amputee to compete at the Olympics in 2012, the athlete was found guilty of murder by the Supreme Court of Appeal in 2015.