Police investigated Friday whether a feud sparked the fatal shooting of hip-hop legend Jam Master Jay, even as skeptical friends and family mourned the beloved music pioneer from Run-DMC.
"There's no reason," the victim's teenage son, Jason Mizell Jr., said Thursday. "He didn't really do anything wrong."
The 37-year-old rap star, whose real name was Jason Mizell, was shot once in the head at close range with a .40-caliber semiautomatic in the Wednesday night attack on the second floor of his Queens recording studio.
Two witnesses told investigators conflicting stories about the killing, police said.
A woman who had shown up to use the studio said that two armed attackers were buzzed into the three-room facility about 7:30 p.m. and opened fire almost immediately.
Police recovered two shell casings from the shooting, which took place as Mizell played video games in a lounge with a 25-year old man, who was shot in the leg.
The wounded man, Uriel Rincon, who was released from a hospital Thursday, told investigators that one masked man opened fire after a struggle.
Three other people said they were in the studio room and did not witness the killing, police said.
Witnesses were being questioned by police Thursday in fresh rounds of interviews, said a law enforcement source who spoke on condition of anonymity.
"They're checking out varying theories, including, 'Was it the result of a personal feud? Was it linked to this East Coast/West Coast rappers?' and other possible motives," the law enforcement source said.
Another source, also speaking anonymously, said: "They're looking at some sort of dispute, anything from a personal dispute to some kind of rap rivalry."
By Thursday evening police had not established a motive or identified any suspects.
Many in the rap industry questioned whether Mizell, known as a family man and social activist, could ever be caught in a violent flare-up — especially a bi-coastal feud that seemed to have little to do with him.
"Before the media rushes to attribute this to East Coast-West Coast violence, they should examine Run-DMC's two decades of contributions and Jam Master Jay's personal character," said hip-hop mogul Russell Simmons, whose brother, Joseph "Run" Simmons, founded the group with Mizell and Darryl "DMC" McDaniels.
Chuck D, the founder of the hip-hop group Public Enemy, blamed record companies and the advertising for perpetuating "a climate of violence" in the rap industry.
"When it comes to us, we're disposable commodities," he said.
"It's a shame that another artist has been murdered, and it's leaving a bad taste in a lot of people's mouths toward hip-hop," local Queens R&B artist Andre Bruce told Fox News. "We’re getting a lot of undeserved negative press."
Bereaved fans outside the crime scene laid flowers, candles, personal notes and an Adidas sneaker — a reference to the group's hit song "My Adidas" — with "R.I.P JMJ" handwritten in marker.
"He's one of the rap pioneers; there are only a couple of others, such as LL Cool J, who have maintained career longevity in this game like Run-DMC has," Angela Young, A&R coordinator at J Records, told Fox News.
"Another fallen angel," she said.
Police investigating Mizell's shooting discovered what one source described as a "credible threat" against rapper 50 Cent, whose Thursday night show planned for a midtown Manhattan nightclub was canceled on their recommendation. 50 Cent was under police guard Thursday.
But Chris Lighty, 50 Cent's manager, said he doubted the killing and the threat report were linked.
"There's a threat against anyone in this business every day," he said.
He said he had no inkling of who would want to harm Mizell, who brought about much of 50 Cent's early success by discovering him and producing his first album about five years ago.
"This is the worst thing that could happen to a guy that has nothing but kindness to spread," Lighty said of Mizell. "He's an icon in our business. It's a disaster in our community."
Fox News' Garett R. Nadrich and The Associated Press contributed to this report.