Trina and Wilbrent Bain
Wilbrent Bain, 23-year-old brother of hip-hop star Trina, shot and killed outside his mother's home 

US rapper Trina is mourning the death of her younger brother Wilbrent "Gonk" Bain after he was shot dead outside his mother's home in Miami.

The hip-hop star, born Katrina Taylor, was inconsolable after hearing the news of her 23-year-old sibling's murder, reports.

Bain was allegedly killed by former friend Ron Dobson after an argument between the pair escalated.

Police have arrested and charged Dobson with second-degree murder.

The 27-year-old suspect is accused of getting off his bicycle and shooting the victim multiple times with a firearm that he pulled from his waistband. He has reportedly admitted to being involved in the killing.

"It hit me hard because I just talked to him. This killing has to stop. It has to. All of us grew up together and that's just senseless," a neighbour said.

"It's a gun problem more than anything because anyone can just get a gun. I guarantee if you walk around this neighborhood now I bet you you'll get it."

Family friend Rev Gary Johnson described Bain, a father-of-two, as a "good kid".

"It's unfortunate. It's a terrible tragedy, " he told NBC Miami.

Trina, known for hits including Here We Go and One Minute Man is yet to comment on her brother' death. A picture of the pair on his graduation day has been added to her Facebook page.