Governor Dinwiddie sent Washington back to the Ohio Country to protect an Ohio Company group building a fort at present-day Pittsburgh, Pennsylvania. Before he reached the area, a French force drove out the company's crew and began construction of Fort Duquesne. With Mingo allies led by Tanacharison, Washington and some of his militia unit ambushed a French scouting party of some 30 men, led by Joseph Coulon de Jumonville; Jumonville was killed, and there are contradictory accounts of his death. The French responded by attacking and capturing Washington at Fort Necessity in July 1754. He was allowed to return with his troops to Virginia. The experience demonstrated Washington's bravery, initiative, inexperience and impetuosity. These events had international consequences; the French accused Washington of assassinating Jumonville, who they claimed was on a diplomatic mission similar to Washington's 1753 mission. Both France and Britain responded by sending troops to North America in 1755, although war was not formally declared until 1756.