Three young men looking to buy marijuana from a "friend of a friend" ended up getting robbed at gunpoint on the southwest side, Madison police reported.

Police said the robbery happened at about 9:45 p.m. Tuesday in the 2700 block of Cimarron Trail near Mesa Court.

According to the police report, the three young men -- an 18-year-old from Madison, a 17-year-old from Verona and a 19-year-old from Fitchburg -- were out celebrating the 17-year-old's birthday and planned to buy some pot.

"The trio drove to a park on Cimarron Trail where they met up with this friend of a friend," said police spokesman Joel DeSpain.

A stranger also showed up, toting a handgun.

"The would-be marijuana dealer and the stranger carried on as if they did not know each other," DeSpain said. "The gunman threatened to kill the victims, and then robbed them of money, a cell phone and a backpack."

The suspect was described as a black male, 20-25 years old, 5 feet 10 inches to 6 feet 1 inches tall, 150 to 175 pounds, with short hair, and wearing a long black T-shirt.