Wanchalerm Kaiklang’s relatives took him to Si Khiew police station to confess to robbing Sukanuya Raksasat, 25, a teacher at Ban Kudnoi School in the same district on September 27.
Both were riding motorcycles when Wanchalerm, 37, allegedly stopped her about two kilometres from the school, seized her valuables, attempted to sexually assault her and left her with five stab wounds to the chest.
Wanchalerm has been working at a vehicle repair garage in nearby Sung None district.
Police said he admitted to several successful robberies since being released from jail late last year.
He’d spent seven years in prison for a robbery in Nakhon Ratchasima.