Detectives from Metropolitan Police Division 2 and Sai Mai Police Station have arrested a 44-year-old delivery rider who stabbed a 16-year-old boy to death following a motorcycle collision in Sai Mai. The suspect said, "The incident happened so fast, I didn’t know the victim was a child." Also, "The situation escalated quickly." They added they did not realize the victim was a minor.
The case involves Mr. Witwatch or Moo Plusawat, 16, a motorcycle delivery driver using a Honda Giorno with license plate 9 ขข 8509 Bangkok. He was stabbed in the right chest above the nipple with a sharp knife, suffering a fatal wound on the sidewalk near the entrance of Soi Sai Mai 74/ก, Sai Mai subdistrict and district, Bangkok, late last night (20 Dec). Good Samaritans recorded the incident on a dashcam. Investigators identified the suspect as Mr. Thongchai Thabprem, 44, a delivery rider riding a white Honda Wave motorcycle, license plate 9 ขก 7206 Bangkok, who fled the scene. The stabbing occurred after the motorcycles collided and a chase ensued, leading the suspect to assault and stab the victim to death before escaping, as previously reported.
At 16:00 on 21 Dec, Pol. Maj. Gen. Kiattikul Sonthien, Commander of Metropolitan Police Division 2, and Pol. Col. Saksit Meesawat, Deputy Commander, received reports from Pol. Col. Athadee Sermsuk, Chief of Investigation Division, Metropolitan Police Division 2; Pol. Col. Thanatpong Kiran, Chief of Sai Mai Police Station; Pol. Lt. Col. Ditsayadech Yimyam, Deputy Chief of Investigation, Sai Mai Police; Pol. Lt. Col. Thanaphat Kamlangraeng, Investigator, Metropolitan Police Division 2; and Pol. Lt. Col. Paijit Nusiwao, Investigator, Sai Mai Police, along with investigation teams from both units.
They successfully tracked down and arrested Mr. Thongchai Thabprem, 44, who was wanted under the Min Buri Criminal Court arrest warrant No. จ.1841/2568 dated 21 Dec 2025, charged with "intentional homicide" and "carrying a knife openly or without reasonable cause in a city or village." Confiscated evidence includes the outfit worn on the day, a pair of bloodstained sneakers, and the white Honda Wave motorcycle with license plate 9 ขก 7206 Bangkok, which was abandoned in Bang Phli district. The arrest took place at a house in Bang Phli Noi subdistrict, Bang Bo district, Samut Prakan province.
Investigations revealed that after the incident, the suspect fled by motorcycle into Bang Bo district, Samut Prakan province, removed the license plate, and left it in Bang Phli area to conceal his escape.
Later at 18:30 at Sai Mai Police Station, detectives from Sai Mai Police and Metropolitan Police Division 2 escorted Mr. Thongchai Thabprem for questioning.
As officers brought Mr. Thongchai out of the vehicle, reporters asked why he committed the crime. Mr. Thongchai responded, "The incident happened so fast. I didn’t know the victim was a child. The problem arose from a misunderstanding and a clash of views. We should have thought more before acting. Honestly, I feel very sorry."
Initially, authorities are preparing to transfer him to the investigators to file charges according to the arrest warrant and to arrange for his detention at Min Buri Criminal Court.