Some in-stadium celebrations for Colombia's home team Atletico NacionalAfter the South American professional club tournament Copa Libertadores finals on Wednesday night—in which Colombia's Atletico Nacional defeated Ecuador's Independiente del Valle 1-0—violence erupted in the streets of Medellín amidst celebrations, and four people were killed, the Associated Press reports.The match was held in Medellín's Atanasio Girardot Sports Complex, but the fighting took place largely outside the stadium, as police registered over 600 street fights. Authorities told the AP that at least 23 people were injured and more than 100 people were arrested.According to the AP, some of the violence occurred hundreds of miles away in Bogota:"One of those killed was wearing the shirt of a rival Medellin club when he was slashed in the neck with a knife. There were also reports that mobs of Nacional fans attacked adversaries in Bogota."The Copa Libertadores final was a two-game series; the first match took place in Ecuador's Estadio Olímpico Atahualpa on July 20th, and ended in a 1-1 draw. The scene in the stadium on Wednesday night was a sea of green and white, Atletico Nacional's colors. Most people involved in the celebrations were predominantly cheering for the same side.