The phenomenon was covered by The Washington Post Tuesday.
According to Nielsen Music, "SAD!" was streamed 48.9 million times in the United States between Thursday, June 14, and Thursday, June 21, a 264 percent increase from the previous week.
Eight other XXXTentacion songs are also in the Billboard Hot 100, including "Moonlight" (No. 16), "Changes" (No. 18) and "Jocelyn Flores" (No. 19).
Billboard reported that XXXTentacion also became the 12th solo rapper to chart at least nine hits on the Hot 100 simultaneously.
XXXTentacion, whose real name was Jahseh Onfoy, was shot outside a Deerfield motorcycle dealership, where deputies said he was approached by two armed people in an apparent robbery. Onfoy was shot by at least one of them and pronounced dead at an area hospital. He was 20 years old.
Related: Rapper XXXTentacion shot, killed in South Florida
One of the men arrested, 22-year-old Dedrick Williams, was charged with first-degree murder without premeditation, among other charges, according to the Palm Beach Post.
An arrest warrant showed Williams is believed to have had an “active part” in the rapper’s death.
Before his death, Onfoy was trying to turn his life around amid allegations of domestic violence against a pregnant woman, his attorney J. David Bogenschutz, told People. The woman, Geneva Ayala, identified herself as his ex-girlfriend and detailed her abuse accusations in a 2017 deposition, Pitchfork previously reported.
While awaiting trial earlier this year, Onfoy was released from house arrest to go on tour and support himself financially.