Police say the rapper, real name Jamell Demons, conspired with another man to make the two male victims look like they had died in a drive-by shooting.
Before his arrest, he said on social media that "lies" were being told about the shootings.
The rapper, 19, has worked with such music artists as Kanye West.
Miramar Police Department announced the murder charges against him on social media, saying Mr Demons had been arrested for murder alongside another man named Cortlen Henry - who uses the rap name YNW Bortlen.
