A Pablo Picasso sketch was stolen from a house near Mexico City.
The painting, a sketch of a man's face, was taken before dawn on Sunday from a house in the suburb of Tlalnepantla, said the official, who was not authorized to give his name. The owner told police the sketch was located in a portfolio that also contained a certificate of authentication.
He told police the sketch was worth US$650,000 (440,000 EUR).
The thieves also took a watch collection and a DVD burner.
Police had no leads in the case.
The choice of the city of Helsinki is not incidental as the capital of Finland had hosted US-Soviet negotiations on the limitation of nuclear stockpiles in 1969