A man jumped from the eighth floor of the Criminal Court building after his son was sentenced there to life imprisonment for murder on Wednesday.
Akkaradet Krueanak survived the fall but was seriously injured and was taken to Rajavithi Hospital.
Pahon Yothin police said they were questioning witnesses and would talk to Mr Akkradet after he recovers.
The man had attended the court to hear the sentencing in his son's indictment for the murder of Sanchai Wan-ngam on June 30, 2017 at Rajavithi Hospital. Pattarpong surrendered to police in Ayutthaya two days later.
Pattarapong worked as a nursing assistantat the hospital and the victim was on the security staff at the time of the murder, the court was told.
