Nipsey Hussle's killer became further enraged when his first shots didn't finish off the rapper ... and Nipsey talked back to him.

Sources at the scene of Nipsey's murder tell us ... after Eric Holder allegedly shot Nipsey twice and the rapper fell to the ground, Nipsey raised his head and said something to the effect of, "You shot me, you got me, I'm good."

We're told Holder -- who had already started to walk away -- turned around and walked back in Nipsey's direction when he realized the rapper was still alive. That's when Holder fired additional shots at Nipsey ... those bullets, eyewitnesses believe, that killed him.

In the surveillance video, you clearly see Nipsey -- who was wearing a white bandana -- raise his head after the initial shots were fired. You can also see Holder approach Nipsey while he lay on the ground, fire more shots, back off, fire again and kick him before running into an alley.

Holder was arrested in Los Angeles Tuesday and has since been charged with 1 count of murder, 2 counts of attempted murder and 1 count of possession of a firearm by a felon. His bond is $5 million. An unidentified female who drove Holder away from the crime scene was questioned and released.

As for Nipsey's funeral ... our sources say it will be taking place on Thursday at the Staples Center -- in order to accommodate everyone who wants to attend. Those close to the rapper were scoping out some of L.A.'s biggest venues.