In the late 80s a new style of hip hop was created "gangsta rap", it was a hardcore style of rapping the themes were mostly about crime, drugs, prostitution and life on the streets specially for African Americans living an urban lifestyle. Even if rap is originally from the east coast, specifically from New York City, “gangsta rap” was originated in the west coast, with acts like N.W.A. In the early 90's it became highly popular throughout the whole United States gaining a widespread following. It was frowned upon by many social groups and politicians because of its anti-establishment, raw, decadent and materialistic lyric content as well as the close ties artists and producers of the genre had with actual gangsters. The Bloods and The Crips, two extremely violent gangs that originated from Los Angeles but had nationwide presence, made up mostly of African Americans, were deeply involved with the movement in all its levels.
Death Row Records, a record company from Los Angeles dominated the genre led by Marion “Suge” Knight and Andre “Dr. Dre” Young, producing many of the most successful rap artist at the time (Snoop Dogg, Nate Dogg, The Dogg Pound). Internal problems started arising in Death Row, Suge Knight had increased his control over the label inviting many of his close friends, most being part of the deadly Bloods gang, Dr. Dre ended up leaving the label to start one of its own.
Meanwhile, gangsta rap in the east coast started flourishing, many rappers becoming very famous, rivaling the west coast rappers. Bad Boy Records, lead by Sean Combs "Puff Daddy" started dominating the east coast scene with rappers like Christopher George Latore Wallace better known as “The Notorious B.I.G” or "Biggie Smalls" and began to compete against Death Row. This started a west coast - east coast rivalry that would end in a tragic bloodshed.
Problems arose in the beginning, where the rappers and producers appeared at the same award shows and nightclubs. The feud elevated when rappers started calling out to each other through their music, called “dissing”, fueling the tension between the two groups. A turning point in the feud, that would turn things violently occurred when Suge Knight and Sean Combs along with their respective entourages ran into each other at a nightclub in Atlanta, a brawl erupted and close friend of Suge Knight was shot and killed, apparently by one of Sean Combs bodyguards. Suge tried to obtain Sean Combs address through his gang contacts and get revenge through a close collaborator of Sean Combs, when he didn't give them Puffy’s address, Suge and his crew, made up of mostly Blood members and rappers which amongst them was Tupac Amaru Shakur almost beat Puffy’s collaborator to death.
Despite the bitter rivalry between east coast and west coast rappers Biggie and Tupac Shakur were originally friends. Everything changed one night in New York when both of them and their producers were in the same recording studio in different floors. Two armed men entered the building and stole 35,000 dollars worth of jewelry from Tupac, and as he tried to stop their escape he was shot 5 times. Tupac survived the incident but a few days later was convicted for a sexual crime and had to serve (...) time in prison. In prison, fueled by rumors inside the penitentiary, Tupac decided that it was Biggie how had set him up for him to be shot. Biggie denied all claims and was deeply offended by the accusation. Biggie soon after released "Who shot ya" a diss song to the west coast rappers that apparently referred to Tupac, even if Biggie always denied it. Tupac was bailed out of jail by Suge Knight and agreed to sign with Death Row. He released "Hit Em Up" a diss track explicitly aimed at Biggie.