Write me one paragraph explaining why Vince is guilty:

On January 5, 1993, at approximately 3:47 PM, Detective R. Minner, using a confidential informant (CI #507), arranged to purchase cocaine from a suspect known as "Vince," a black male gang member. The CI introduced Minner to Vince at the Home Depot on East Thomas Road in Phoenix, Arizona. Vince sold Minner two pieces of a rock-like substance, believed to be crack cocaine, for $40. After the transaction, a vehicle with Arizona license plates was identified as the one Vince arrived in.

The substance was later tested and confirmed to be cocaine, and it was documented and placed into evidence. Following this, on January 12, 1993, Detective Minner arranged a second purchase of cocaine from Vince after obtaining his pager number through CI #507. Minner met Vince at a Circle K store, where Vince indicated he would need to retrieve the drugs from another location. After waiting, Vince returned and sold Minner two more pieces of cocaine for $40, while also advising him on pricing for smaller quantities.

The second set of drugs was also collected as evidence and later confirmed to be cocaine. The case against Vince for two counts of sale of narcotic drugs from both purchases was submitted to the Maricopa County Attorney's Office for prosecution.