The 17-year-old aspiring rapper fatally shot at the weekend recorded a rap video which was uploaded to YouTube challenging a rival group one month before his death.
Rhyhiem Ainsworth Barton, who was shot and killed in Kennington, south London on Saturday, was reportedly a member of Moscow17.
The group had frequent rap competitions - known as "drills" - with Zone 2, a rival crew from Peckham.
In the track titled City Of God, Rhyhiem - who rapped under the name GB - is believed to have challenged Zone 2 by asking "how you gonna make it even".
The video, which was removed from YouTube by Moscow17 but uploaded again by another user following Rhyhiem's death, was the most recent in several "drill" battles between the two groups.
Their violent rivalry is evident in another track where Moscow17 - who occasionally used the nickname "the Russians" - told their rivals to "check the scoreboard".
Zone 2 responded with a video telling their opposition they will "roll up and burst them".
Rhyhiem's death was one of five shootings in London over the Bank Holiday weekend.
Since he was killed, a montage video of him rapping alongside fellow Moscow17 members has been uploaded to YouTube and viewed over 29,000 times.
Comments below the video say Rhyhiem "jinxed himself" by challenging the rival crew in the City Of God rap just four weeks before he was killed.