These transfers of responsibility should be considered not only in respect to the specific operations against the North, but also to the level of covert military operation in the South in the upcoming months. This transfer also cut the experienced MG Edward Lansdale out of the process, as while he was a U.S. Air Force officer, the military saw him as belonging to CIA. Intelligence support Also in May, the first U.S. signals intelligence unit, from the Army Security Agency under National Security Agency control, entered Vietnam operating under the cover name "3rd Radio Research Unit". Organizationally, it provided support to MAAG-V, and trained ARVN personnel, the latter within security constraints. The general policy, throughout the war, was that ARVN intelligence personnel were not given access above the collateral SECRET (i.e., with no access to material with the additional special restrictions of "code word" communications intelligence (CCO or SI). Their principal initial responsibility was direction finding of Viet Cong radio transmitters, which they started doing from vehicles equipped with sensors. On December 22, 1961, an Army Security Agency soldier, SP4 James T. Davis, was killed in an ambush leading an ARVN squad on one of these direction finding missions. After Johnson became President of the United States several years later, he referred to Davis in a speech as the first American killed in Vietnam; in reality, there had been fifteen battle deaths before Davis. Covert U.S. air support enters the South More U.S. personnel, officially designated as advisors, arrived in the South and took an increasingly active, although covert, role. In October, a U.S. Air Force special operations squadron, part of the 4400th CCTS, deployed to SVN, officially in a role of advising and training. The aircraft were painted in South Vietnamese colors, and the aircrew wore uniforms without insignia and without U.S. ID. Sending military forces to South Vietnam was a violation of the Geneva Accords of 1954, and the U.S. wanted plausible deniability. The deployment package consisted of 155 airmen, eight T-28s, and four modified and redesignated SC-47s and subsequently received B-26s. U.S. personnel flew combat as long as a VNAF person was aboard. FARM GATE stayed covert until after the Gulf of Tonkin incident. Building the South Vietnamese Civil Irregular Defense Groups Under the operational control of the Central Intelligence Agency, initial U.S. Army Special Forces involvement came in October, with the Rade people of southern Vietnam.