Sommart Chokekuea, 40, reported to police early this morning that he was attacked by three masked men who broke into his house on Soi Nak in Chalong with the aim of emptying his safe.
Despite the masks, Mr Sommart recognised one of the three as his former partner, Sonthaya Thanawaroa, 27.
Mr Sommart said the trio covered him with a blanket and Sonthaya punched him repeatedly and then stabbed him in his chin when he fought back.
After attacked Mr Sommart, Sonthaya and others attempted to open the safe but Sonthaya failed to remember the combination for the lock.
This set off the alarm. The three rushed out of the house and jumped on a motorbike, taking the safe with them.
Police are now tracking them down.