Rap legend Jam Master Jay lay, mortally wounded, on his studio floor. One of his aides was in pain from a gunshot to the leg. Another was crying and screaming on the floor.

Dashing in from an adjoining room, Randy Allen took in the bloody scene, grabbed a gun and charged outside to seek whoever had done it, he testified Tuesday at a federal murder trial over the October 2002 shooting of the Run-DMC star in the New York borough of Queens.

Allen, who was the DJ's business partner and childhood friend, told jurors he wanted “to try at least to see who it was.” He didn't see anyone running from the studio, he said, so he stashed the gun in the wheel well of a parked car and ran to a nearby police station for help.

Allen was the last to testify among five prosecution witnesses who say they were in various parts of the studio when the turntable titan, born Jason Mizell, was killed. But there is more to come in the trial of what has been one of the highest-profile and hardest-to-solve killings in the hip-hop world.

The defendants, Karl Jordan Jr. and Ronald Washington, have pleaded not guilty.

Allen said he was in the studio's control room and heard two shots in the adjacent lounge area but didn't see the attacker or attackers.

But he said that in the ensuing days, wounded eyewitness and aide Uriel “Tony” Rincon told him that Jordan fired the gun and Washington was there.

Allen added that Lydia High, who is his sister and was the business manager at Mizell's record label, told him that Washington ordered her at gunpoint to hit the floor and the shots were fired by a man with a tattooed neck. Jordan has such a tattoo.

Rincon and High both testified likewise earlier in the trial. But neither they nor Allen told investigators initially, or indeed for years, that the eyewitnesses could identify either man. Allen said he had wanted to leave it up to those two to tell, since he hadn't seen the shooting himself.

“The only person you saw with a gun in hand was you, right?” asked one of Jordan's lawyers, Mark DeMarco.

Allen said Mizell had been keeping that gun by his side. The witness said he grabbed it “for protection" before running out to look for anyone who might be running away.

Defense attorneys pointed to a signed statement that Allen gave to police hours after the shooting, in which he said he heard three to six shots and saw a heavyset man in a dark jacket going down the building's stairs after the shooting.

Allen said he didn't recall saying any of that.

Prosecutors allege that Mizell was killed out of “greed and revenge.” Under their theory, Mizell — known for his anti-drug advocacy with Run-DMC — was arranging to sell a sizeable amount of cocaine in Baltimore, and Washington and Jordan were about to lose out on a piece of the profits.

Christopher Burrell, a neighborhood friend whom Mizell had taken under his wing in the music business, told jurors Tuesday that he overheard the DJ talking in summer 2002 about “setting up Tinard in Baltimore ... to sell drugs or whatever.” Tinard is Washington's nickname.

But an admitted dealer who said he was the Baltimore connection on the deal testified Monday that he had ill will toward Washington and told Mizell there was no deal if Washington was involved.

The defense has not yet had its turn to present evidence.

Attorneys for Washington, 59, have said prosecutors brought a thin and illogical case against a down-and-out drinker who was anything but angry toward the famous friend who supported him.

Jordan, 40, who was Mizell’s godson, has said through his lawyers that he was elsewhere when the shooting happened and has alibi witnesses.