After meeting with President James K. Polk, he left Washington, D.C. on May 15, 1845. He raised a group of 62 volunteers in Saint Louis. He arrived at Sutter's Fort, on December 10, 1845. He went to Monterrey, California, to talk with the American consul, Thomas Larkin, and Mexican major-domo Jose Castro. In 1846, with the arrival of the USS Congress, Fremont was appointed lieutenant colonel of the California Battalion, also called U.S. Mounted Rifles, which he had helped form with his survey crew and volunteers from the Bear Flag Republic, now totaling 428 men. In June 1846, at San Rafael mission, Fremont sent three men, one of which was Kit Carson, to confront three unarmed men debarking from a boat at Point San Pedro. Kit Carson asked Fremont whether they should be taken prisoner. Fremont replied, "I have got no room for prisoners." They then advanced on the three and deliberately shot and killed them. One of them was an old and respected Californian, Don Jose R. Berreyesa, whose son was the Alcalde of Sonoma who had been recently imprisoned by Fremont. The two others were twin brothers and sons of Don Francisco de Haro of Yerba Buena, who had served two terms as the first and third Alcalde of Yerba Buena (later named San Francisco). These murders were observed by Jasper O'Farrell, a famous architect and designer of San Francisco, who wrote a letter detailing it to the Los Angeles Star published on September 27, 1856. This eyewitness account, together with others, were widely published during the presidential election of 1856, which featured Fremont as the first anti-slavery Republican nominee versus Democrat James Buchanan. It is widely speculated that this incident, together with other military blunders, sunk Fremont's political aspirations. In late 1846 Fremont, acting under orders from Commodore Robert F. Stockton, led a military expedition of 300 men to capture Santa Barbara, California, during the Mexican-American War. Fremont led his unit over the Santa Ynez Mountains at San Marcos Pass in a rainstorm on the night of December 24, 1846. In spite of losing many of his horses, mules and cannons, which slid down the muddy slopes during the rainy night, his men regrouped in the foothills the next morning, and captured the presidio without bloodshed, thereby capturing the town. A few days later Fremont led his men southeast toward Los Angeles, accepting the surrender of the leader Andres Pico and signing the Treaty of Cahuenga on January 13, 1847, which terminated the war in upper California. On January 16, 1847, Commodore Stockton appointed Fremont military governor of California following the Treaty of Cahuenga. However, U.S. Army Brig. Gen. Stephen Watts Kearny, who outranked Fremont (and who arguably had the same rank as Stockton, which was one star), said he had orders from the U.S. president and secretary of war to serve as governor. He asked Fremont to give up the governorship, which the latter stubbornly refused to do for a time. Kearny gave Fremont several opportunities to change his position. When they arrived at Fort Leavenworth in August 1847, Kearny arrested Fremont and brought him to Washington, for court martial. Fremont was convicted of mutiny, disobedience of a superior officer and military misconduct. While approving the court's decision, Pres. James K. Polk quickly commuted his sentence of dishonorable discharge due to his services and Fremont resigned.