Finland’s border guard service said Friday that a suspected violation of its airspace by Russia earlier this week is now believed to have involved four warplanes instead of the initially reported one. “As the investigation progresses, it has become apparent that in addition to the one Russian plane reported earlier, there is also reason to suspect three other planes of territorial infringement,” the border service said in a statement. Finnish authorities said the “violation is suspected to have occurred by a four-plane division, which included two bomber and two fighter-class aircraft,” adding…