Fans had gathered to remember the rapper, who was shot dead in LA earlier last month, but the procession descended into chaos the crowds surged into the streets.
It has since emerged that shots were fired at a spot along the route shortly after the car carrying Hussle’s body had passed by.
The fatality was confirmed by LAPD Chief Michel Moore in a statement posted on Twitter.
He wrote: “In the midst of this procession we have a multi-4 shooting at 103 St and Main St. Victims are 3 Male Blacks and 1 Female Black – ages from 30-50 years old.
“Tragically one is deceased. Suspects in gray Hyundai fired on the victims. We must stop this senseless violence.”
Moore added: “Today 10 of thousand gathered in tribute 2 Nipsey Hussle.
“LAPD showed the world that the men and women of this Department are compassionate and without peer.
“They worked seamlessly with our community advocates to keep the peace. I’m grateful.”
Around 21,000 people headed to the service at the Staples Center and thousands more filled the streets of LA to remember the late musician.
Among the stars at the service was Stevie Wonder, who called for stronger gun control laws before playing the song Tears In Heaven by Eric Clapton.
He said: “It is a heartbreak to again lose a member of our family. It is a heartbreak because it’s so unnecessary.
“It is so painful to know that we don’t have enough people taking a position that says, ‘listen, we must have stronger gun laws’.
“It is unacceptable. It is almost like the world is becoming blind.”
Snoop Dogg addressed his late friend, saying: “You are a peace advocate, Nip. That’s what you are.”
After the service a silver hearse carrying Hussle’s coffin drove 25 miles through the city to a funeral home in the Crenshaw district, where the rapper was born in 1985.
The rapper was shot dead outside a clothing store he owned on March 31. He was 33.
Eric Holder, 29, has been charged with killing Hussle and has pleaded not guilty.