In mid-January 1968 the 1st Battalion, 3rd Marines was working out of the Quang Tri Combat Base, responsible for defending the base itself, for combat patrols around the base, and for convoy escort and reaction force duties along Highway QL-1. While the 1/3 Command Chronology for January 1968 lacks both a day-by-day narrative and the operations log, 1/3's activities through 20 Jan are covered in the 3rd MarDiv's Operation OSCEOLA Situation Reports.
The OSCEOLA SITREPS for 13 Jan contain three references to Bravo 1/3:
SITREP #339 (131200-1800): "131345H B/1/3 at YD 285524 Marine detonated unknown type mine. Results 4 USMC WIAE"
SITREP #340 (131800-2400): "At 131815H B/1/3 at YD 279524 A Marine tripped M-26 grenade rigged as mine. Results 2 WIA med[evaced]"
"At 131845H B/1/3 at YD 278524 received approximately 20 rounds of small arms fire from unknown number of VC. Returned small arms fire and UH-1E armed [helicopter]. Area searched, no evidence of enemy casualties."
The grid coordinates place Bravo 1/3 on the west bank of the Thach Han River about 4 kilometers east-southeast of Dong Ha. It seems clear that Corporal Bagnall was injured in one of the two mine incidents and died during or shortly after being evacuated.