Jelani Maraj, the brother of rapper Nicki Minaj, has been found guilty of predatory sexual assault.

Maraj, 38, was on trial for raping an 11-year-old girl on multiple occasions at his Long Island home. He was charged with the crime in 2015 and found guilty at Nassau County court, New York, this week. Maraj faces the potential of 25 years to life in prison.

Rapper Nicki Minaj. Photograph: Dimitrios Kambouris/Getty Images

Neither Maraj nor his sister, whose birth name is Onika Tanya Maraj, testified in the trial. The child, now 14, and her younger brother testified. The defence lawyer claimed the allegations were fabricated by the child’s mother in order to extort $25m (£19m) from Nicki Minaj.

James R Ray III, a civil attorney who briefly represented the mother, testified that he did demand a $25m legal settlement from Jelani Maraj after he had been arrested, but said the girl’s mother was unaware of the demand.

“She was never involved as far as what we did,” Ray III testified. The woman later fired him as her attorney.

Maraj is set to be sentenced on 14 December. His lawyer has said he will appeal the judgment.