This was a US special forces operation to parachute a party of the Office of Strategic Services’ Company A, 261st Reconnaissance Battalion, into German-occupied Italy to aid local resistance forces (4 March/22 May 1945).
The group’s mission was to harass German garrisons, disrupt German communications, gather and transmit intelligence, and establish liaison, supply, arm and train partisan units in the lower Valtellina region adjoining that in which the 'Spokane' and 'Sewanee' groups were operating.
Sharing flights with the personnel of the 'Spokane' and 'Sewanee' groups on 4 March (five men) and 4 April (eight men) to the drop zones 'Beet' near Livigno and 'Pappy' near Eita, the five personnel of the first element of the 'Santee' group, under the command of Captain Victor J. Giannino, gathered at Fusino, which became the element’s initial base. The Amerians established links with the local partisan forces, providing and training them with US equipment, and undertaking a reconnaissance of the area as far to the north as the Swiss border. There were skirmishes along the Val Grosina between partisans, accompanied by operational group personnel, and opponents who included the Germans, Italian fascists and Vichy French Milice française. After one such engagement, on the night of April 13/14, some 30 opponents were reported killed. On April 18 300 French collaborators and Italian fascists moving up the valley ran into heavy partisan fire, and lost more than 100 persons killed or wounded in exchange for only two partisans killed.
At the end of April 1st Lieutenant Michael A. DeMarco with part of the operational group fought in Grosotto to protect the local partisan base. At the same time Giannino and his part of the group fought in Tirano and were instrumental in the surrender of more than 1,200 Germans, Italian fascists and Vichy French miliciens. On 29 April, at San Giacomo, another detachment of 350 surrendered to the partisans and Americans, who on the following day entered the town of Sondrio. The entire Valtellina area was liberated and the German and Italian fascist forces were either captured or surrendered along with large quantities of arms, ammunition and supplies. The captured men were placed under the control of partisan units, and their weapons were used by partisans, other Italian citizens and the men of the operational group.
The operational group established a headquarters in Tirano and arranged for airdrops of food, and on 22 May 22 returned to their base in Siena.