ANDOVER, Minn. --Authorities have arrested a third suspect in the Friday night hit-and-run death of a teenager in Andover, which they now are labeling second-degree murder.

Investigators announced Sunday that the death of Tristan Gene Robinson, 17, of Nowthen, was not an accident as previously reported, but that the teen was run down as part of a drug-related robbery gone bad in the  city north of the Twin Cities.

On Monday morning, 19-year-old suspect Loren Gafner of St. Francis was arrested in Isanti after a state trooper saw him. On Sunday, 17-year-old suspect Daveion Maddox of St. Francis was arrested in a vehicle in Oak Grove. Another juvenile from St. Francis, who has not been identified, was also taken into custody Sunday.

Police believe Gafner was driving the 2005 Mercury Montego that struck Robinson on Friday night. Police say they have recovered the car.

Robinson was struck about 6:20 p.m. Friday after he left a friend’s house. His friends reported that they “heard a dull collision sound followed by screeching tires,” police said. “They went outside to investigate and saw their friend in the street with multiple injuries. They did not see a vehicle.”

Robinson was pronounced dead at the scene.

Police ask anyone with information to call the Anoka County sheriff’s office at 763- 427-1212 or to call 911.