Darden is quitting the case after filing a motion to withdraw as Eric Holder's lawyer following a hearing on Friday, May 10 in Los Angeles.
The famous prosecutor reveals threats on his life and his kids' lives prompted him to step down.
A statement reads: "I cannot understand why in 2019 some people would deny a black man his 6th Amendment right to counsel of his choice. Or why defending such a man should invite threats not only against me but against my children too."
Darden admits he received his fair share of threats as he tried to put Simpson behind bars for the murder of his wife in 1995 and he's dismayed the same "cowards" are still out there.
"Just as they were in 1995 - Cowards never change," he adds. "These days these cowards don't send letters instead they sit anonymously behind keyboards threatening a man's mother and children.
"To those who issued those threats to my children please pay close attention so there is no misunderstanding. Later. F**K YOU!"
Holder is accused of gunning down Nipsey outside his Marathon Clothing store in Los Angeles on March 31.