According to US news sites, Jelani appeared at Nassau County, New York court on Thursday, facing charges of first degree rape and first-degree course of sexual conduct against a child.
Details, including the victim’s gender, have been kept private, but each crime carries a sentence of up to 25 years in the US.
Earlier this year Nicki – real name Onika Maraj – paid for Jelani and his longterm partner Jacqueline Robinson to get married in a $30,000 ceremony.
Nicki, 32, proudly shared snaps from her brother’s big day, and gushed over him on social media.
Quoting lyrics from the song by Monica, Nicki wrote: “I would cross the ocean for u. I would go & bring you the moon. Promise u. For u I will.”
The hip-hop superstar added: “I love my brother so much man. Can’t believe I cried during his wedding and his first dance like a pink.
“May God bless him and his union. Tonight has been one of my favourite nights of all time. I do anything to see my brothers smile [sic].”
Jelani was freed from jail after posting £66,000 bail, according to court records.
No further details have been released about the case.