I know there is a few people on here interested in this particular subject so I've done a rundown of some of the major rap labels that have been caught up in some trouble over the years.

The Inc (Formerly Murder Inc)
new york
Mid 90s- present
Founders- Irv Gotti, Chris Gotti, Ja Rule
Notable Artists-Ja Rule,Ashanti,Rah Digga, Lloyd

Criminal associations- Kenneth "Supreme"Mcgriff. A convicted drug lord and leader of the supreme team drug gang that operated a $200,000 dollar a day crack cocaine operation in queens and harlem during the 1980s. After serving 10 years was released in 97 and became very close with irv gotti.Investigators have alleged that McGriff, 43, bankrolled Gotti and has "provided Murder, Inc. with 'muscle'--threats, violence, and intimidation."

Activity-Drug trafficking in NY and Baltimore, money laundering, attempted murder, murder.

Connected violence- murders of Eric Smith,Troy Singleton,Karon Clarret and one of his friends, Jam Master Jay. Attempted murder of 50 Cent.

Thizz Entertainment(formerly Romp Records)
Bay Area
Founders-Mac Dre, Jamal Diggs, Simon'kilo curt' Curtis
Notable artists-E40, Mac Mall, Yukmouth, Keak da Sneak

Criminal Associations- 1980s- 1990s: Romper Room gang. To finance there music ventures Dre, Diggs and curtis trafficked drugs and robbed banks and businesses until their arrests 1992. Dre was released and continued to perform until his shooting and murder in kansas city in 2004.
2012:CUrrent head of Thizz Ent Michael Lott and numerous rappers and associates were recently indicted for running a large scale ecstasy trafficking that distributed in vallejo, bay area,oklahoma, New york, atlanta and milwaukee.

Connected violence-Anthony 'Fat Tone' Watkins and Jermaine 'Cowboy' Aikens were killed in retaliation for Mac Dres murder.

BMF Entertainment (or the Black Mafia Family)
Detroit, Atlanta, Los Angeles
1980s- 2005
Founders and associates-Demetrius 'Big Meech' Flennory, Terry'southwest t' flennory,Chad'J-Bo' Brown, Eric 'Slim' Bivens, Fleming Daniels
Notable Artists-Young Jeezy,Bleu Davinci

Criminal associations-The Black Mafia Family (BMF), was a drug trafficking organization originally based in Detroit, Michigan. Founded by the Flenory brothers Demetrius and Terry, the organization began in the late 1980s. By the year 2000, they had established cocaine distribution cells in cities throughout the United States. Through their Los Angeles-based drug source, they had direct links to Mexican-based drug cartels.They established two main hubs for their operation: the Atlanta, Georgia hub, for distribution, was operated by older brother Demetrius, while the Los Angeles, California hub was operated by Terry to handle incoming shipments from Mexico. The organisation moved into the hip hop business during 2000 and had associations with stars such as jay z, nelly and fabulous. They also kept ties to various street gangs such as the campanella park piru bloods in compton who were supplying them with drugs that they would then ship across the country.

Acticvity- Nationwide cocaine trafficking, money laundering and murder.

Connected violence- Murders of P-Diddy associate Anthony 'wolf' Jones, Rashanniball 'Prince'Drummond, Ulysses Hackett and Misty Carter

Death Row Records
Los Angeles
1991-2006
Founders and associates-Marion 'Suge' Knight, Michael 'Harry O' Harris, Jake Robles,David Mack, Kevin Gaines, Rafael Perez.
Notable artists-Dr Dre,Snoop Dogg,Tupac,Warren G,DJ Quick,Nate Dogg

Criminal Associations- One of the most successful music labels of all time, death row records sales climbed to $125 million in just four years. However it was also marred in controversy from its inception, with links to gangs, violence,threats,police scandals and the culminating murders of Tupac Shakur and Biggie Smalls. The label was strongly tied to the MOB piru bloods gang through Knight and his enforcer Jake Robles but employed crips as well.

Activity-Alledged gang activity,threats,intimidation, assaults, kidnapping and murder.

Connected violence- Murders of tupac shakur, christopher wallace, southside crip kelly jamerson, jake robles, randy 'stretch' walker, a bounty hunter blood and drug dealer named bruce and his girlfriends slaying a week later.

Czar Entertainment (or the rosemond organisation)
1990s-present
Founders and associates- Jimmy 'the Henchman' Rosemond, Khalil Abdullah, Dexter Issac.
Notable artists-Game,Brandy, Akon, Shyne, Sean Kingston, Gucci Mane

Criminal associations- On June 5, 2012 Henchman was convicted of drug trafficking, obstruction of justice, firearms violations and other financial crimes associated with his being the head of a multi-million dollar transnational cocaine selling organization. This came after he was indicted in 2011 on federal charges of drug trafficking, money laundering, obstruction and weapons charges. In February 2012, he was arrested for the murder-for-hire of Lodi Mack, an associate of rapper 50 Cent. Authorities found that rosemond was shuttling large quantities of cocaine and cash back and forth from new york and california in music cases and used Universal owned record label Interscopes offices as stash houses for both drugs and money. The investigation also found that the cocaine was being supplied from a number of sources including members of the west coast bloods and crips.

Activity- Inter coastal drug trafficking, money laundering and murder.

Connected violence- Murder of 50 cent associate Lodi Mack, another informant, dexter isaac has stated that Rosemond hired him and others to rob tupac shakur at the quad recording studios in 1994 which resulted in Tupac being shot several times but surviving.