The advance of the "Column" entered Tucson on the twentieth day of May, 1862. Several Americans, among them Sylvester Mowry, formerly of Rhode Island, returned, and being violent in their sympathies with the rebellion, were arrested. Some were sent out of the Territory, while Mowry was sent to Fort Yuma, where he remained incarcerated a long time. About the fifteenth of June, Captain N. S. Davis was relieved from the command of Company K by Lieutenant Pettis, who remained in command, with a short interval, until its final muster out. Captain Davis was on duty in the quartermaster's department. By the first of July, a large part of the "Column" had arrived at Tucson, a large depot of army stores had been brought from California, and preparations were commenced for the movement again of the advance column. Several spies and scouts had been sent forward from Tucson, but as they had not returned, matters were rather uncertain. However, in the first week in July, Company E, First California Infantry, Captain Thomas L. Roberts, and Company B, Second California Cavalry, were ordered to proceed to Apache Pass and hold possession of the water at that point. On the twentieth of July the advance column left Tucson, and on the second day arrived at the San Pedro, twenty-five miles. Here a delay of one day was made to put the fording place in good order for the crossing of the "Column." Information was received here that Captain Roberts' advance into the Apache Pass had been attacked by a large force of the Apaches, under the renowned chief, "Cochise," and after fighting during an entire afternoon had succeeded in driving the Indians, with a loss on our side of several of our men killed and wounded.