
Sukkho Tamseri, 32, who was close to late Pol Maj Gen Prakrom Warunprapha, was handed over to the Crime Suppression Division at 9:30 pm.
Sukho was wanted on an arrest warrant for allegedly having illegal firearms in possession.
Prakrom, who hang himself while custody, was among three earlier suspects, including Suriyan Sujaritpolwong or Moryong.