As part of its normal defense mission, personnel of the regiment spent a large part of their time controlling civilians and regulating traffic, especially water travel. Certain counterintelligence problems confronted the Kimpo Provisional Regiment. A large civilian population, numbering nearly 80,000 natives, lived within the regimental sector. Local restrictions set by the National Police on Kimpo (who cooperated with the KPR in security matters) included the STAYBACK LINE to the north of the peninsula. As a rule, no civilians other than those with daytime farming permits, were allowed beyond this line. Numerous regulations were also issued to control boat traffic. Surrounded by rivers on three sides, there was ample opportunity for enemy agents or line crossers to infiltrate the defense line, despite continuous screening by friendly outposts and waterborne patrols. Two months after the “heavy” June shelling came the August floods, which were more destructive than the artillery had been. The rest of the summer and fall followed a fairly regular, uneventful pattern with customary defense duties, rotation of frontline units, and training exercises. Among the latter were four helicopter demonstrations in October and a five-hour communication CPX (Command Post Exercise) the following month. One episode toward the end of the year created a temporary stir in the daily routine. In late November, two Communist espionage agents and their North Korean guides were apprehended on the west bank of the Han, almost directly east of the Kimpo Airfield. They had crossed the Imjin-Han Rivers by boat, using this normal infiltration route to penetrate the Marine defense net. The agents were seized by National Police on 22 November and their North Korean guides two days later. It was unusual for agents and guides to be captured so closely together. Normal defense measures of the peninsula had assigned separate northern, western, and southern sector units for protection against possible amphibious or overland attacks or--far more likely--enemy infiltration. The following month four more “roving” two-man outposts were established in the western coastal area of the southern sector. Manned from sunset to 30 minutes after sunrise daily by either KPR military personnel or National Police, the outposts occupied different positions each night. They were responsible for checking for proper identification and enforcing the rigid 2100–0500 curfew hours. Another unusual occurrence took place the last four nights of December when a single-engine light aircraft dropped propaganda leaflets in Colonel Harvey C. Tschirgi’s[334] sector. [334] Colonel Tschirgi had taken command of the KPR on 1 December from Colonel Richard H. Crockett, who previously relieved Colonel Staab (the original KPR commander) on 31 August.