The first verse is performed by three of the four members of the rap group Dramacydal who would go on to join 2Pac's Outlawz group (Yaki Kadafi, Kastro, and E.D.I. Mean, in that order), the second by Stretch and the Notorious B.I.G., and the third and last by 2Pac.
Runnin' From tha Police deals with the authors' troubles with the police. The lyrics contain verbal abuse toward police officers, and even allusion the possibility of killing them (two cops is on the milk box, missing, or let's serve these motherfuckers slugs [bullets] as a fuckin' meal), albeit in possible self-defense.
Runnin' From tha Police was supposed to be featured on Shakur's album Thug Life, but it was cut due to heavy criticism of gangsta rap at the time. Subsequently it was intended to be featured on Shakur's album Me Against The World, with a different 2Pac verse, in 1995, but was cut due to the shooting in '94 that would lead to his bitter rivalry with Biggie.
In 2006, Ludacris used a sample of Notorious' first words in his verse (I grew up a fucking screw up / Got introduced to the game / Got an ounce and fucking blew up) as a hook on his single Grew Up a Screw Up.