Lisbon: Portuguese prosecutors said Tuesday they had opened an investigation after footage emerged of a police officer beating a man outside a football stadium as the man's children watched nearby.

The investigation was launched "following a complaint of alleged abuse of power during police intervention," the Porto attorney general said in a statement. Jose Magalhaes, a 43-year-old businessman, was beaten by a police officer as he was exiting the Afonso Henriques stadium Sunday in the northern city of Guimaraes, following Benfica's title-clinching Portuguese league victory.