National police chief Pol Gen Torsak Sukvimol on Tuesday called on the Police General Hospital to submit a report on the treatment it is providing for jailed former premier Thaksin Shinawatra.
The call came after a photo was circulated showing Thaksin wearing a patient's gown and face mask.
The photo, which went viral on social media last week, sparked criticism regarding the special privileges Thaksin may be receiving.
It has been alleged that the picture was circulated on purpose. Critics said it may be intended to give the impression that Thaksin remains seriously ill and needs further hospital treatment outside of prison.
The photo came as Thaksin's out-of-prison hospitalisation deadline of 90 days is due to end on Friday.
On Tuesday, Pol Gen Torsak admitted he knew little about the hospitalisation issue since he was only recently made national police chief.
Thaksin, 74, returned to Thailand on Aug 22 after 15 years of self-imposed exile and was sentenced to a total of eight years in three cases.
However, he was sent from Bangkok Remand Prison to the Police General Hopsital that night for health reasons, and he has remained there since.
One political activist also questioned why Thaksin was not given a short prisoner haircut, which is a requirement under Corrections Department regulations.
