A$AP Rocky 's accuser, former friend and the key witness testified Tuesday that their relationship had long been tense, and came to a head in the days before Rocky is alleged to have fired a handgun at him.

The trial’s key witness, known by the name A$AP Relli, will provide what’s likely to be the trial’s most important piece of testimony when he gets back on the stand.

During the second day of A$AP Rocky's assault trial, the man he is accused of shooting at years earlier on a Hollywood sidewalk took the stand and told jurors he was "furious" when the rapper allegedly pulled on a gun on him.

A$AP Rocky's accuser, former friend and the key witness at his trial is set to take the stand Tuesday afternoon. Rocky, the rapper and partner of Rihanna, has pleaded not guilty to two felony counts of assault with a semiautomatic firearm for allegedly firing at the friend who goes by A$AP Relli.