To apprehend and deliver to the Division Provost Marshal any line crossers encountered who did not possess an authorized pass, regardless of the direction from which such persons entered the DMZ; and
To provide check points on known routes through the zone and observation posts, especially during the hours of reduced visibility, and telephone all suspicious incidents to Regimental S-2.
DMZ Police Company personnel operated in motorized patrol teams and traveled the entire division sector in radio or cargo jeeps. One platoon was kept on a standby basis at camp to serve as a mobile reserve in the event of an emergency. The roving patrols submitted reports of all incidents, which were then compiled in a company report. A copy was submitted to the S-2, the Northern Regiment, and 1st Marine Division G-2.
UNC security measures at all times were strict and uncompromising in the Korean DMZ buffer zone. This included the salvage period, the BIG SWITCH prisoner exchange that took place within the division sector at Freedom Village from 5 August-6 September, and the lengthy nonrepatriate POW settlement that extended through January 1954. In places where the military demarcation line was not marked on the ground or clearly recognizable, the conservative ruling was to stay at least 500 yards south of its estimated location. This applied both to body recovery and salvage operations. The No-Fly line was scrupulously verified.
Alleged violations charged by the CCF/NKPA were checked out with the Marine ground observation posts set up in August to record all movements of fixed-wing (reconnaissance) and rotary aircraft in the area. Helicopters were allowed to fly in the DMZ but no closer than the 500 yard limit from the MDL. Helicopters operating forward of CPs of 5th Marines units having sector responsibility were required to obtain clearance from the ground unit concerned for each flight. Medical evacuation copters, generally, were exempted from this restriction and authorized a standing clearance.
Commitments for the DMZ Police Company increased substantially with arrival of the nonrepatriated POWs at their camp in the DMZ corridor west of the 2d Battalion, 5th Marines area. The Communist “explainers,” as well as Polish and Czech members of the neutral Nations Commission, had to be escorted while in the UN half of the DMZ. This required that a 24-hour checkpoint and escort cadre be established in the zone. As the number of enemy sightings, a daily occurrence in the DMZ, continued to increase, the size of the police patrols increased correspondingly. A typical example was related by a member of the police company:
It was common practice of the Communists to have a group of their men, supposedly their DMZ Police, walk up to the Military Demarcation Line and either stand close to it or step across. When one of our patrols approached in superior numbers to attempt to apprehend them, the Communists would immediately reinforce with more men. This made it necessary to have our patrols at sufficient strength that they could protect themselves from being kidnapped.[674]
[674] Demilitarized Zone Police Co/5 rpt, p. 4, in 5thMar Hist, Folder #4, op. cit.
As these requirements for security increased, the original complement of approximately 5 officers and 99 men became inadequate to patrol the DMZ. By late October the T/O strength of the 1st Provisional Demilitarized Zone Police Company had been increased to 6 officers and 314 men. Authorization for the number of police personnel on duty in the DMZ had similarly been augmented from 50 to 175.
During the September salvage operations, five Marines in the DMZ were taken into custody by the Chinese Communists. Charged with being in unauthorized territory and violating terms of the armistice agreement, they were later returned to United Nations jurisdiction.