A group of senators on Tuesday urged authorities to probe the source of funding for Monday night's gathering at Thammasat University's Rangsit campus, one that was seen to be at risk of offending the monarchy.
Senator Somchai Sawaengkarn, for instance, proposed at a Senate session that the Anti-Money Laundering Office (Amlo), the Department of Special Investigation (DSI) and the Royal Thai Police investigate the money trail behind the "extravagant" gathering claimed to be organised by a group of university students.
Renting the giant LED screen that was used to display images mocking a portrait of His Majesty the King would normally cost hundreds of thousands of baht, said Mr Somchai.
Digital Economy and Society Ministry and Technology Crime Suppression Division were also urged to track and take legal action against people who disseminated copies of the illegal content on social media, he said.
Offending the monarchy is illegal under Thailand's lese majeste law.
Mr Somchai also called on the police to petition the court to withdraw bail granted to human rights lawyer Arnon Nampa and political activist Panupong Chadnok, known as "Mike Rayong". They have been allowed out on bail in a sedition case on the condition that they must not repeat the offences they are accused of.
They were caught in a video clip making a speech at Monday night's gathering offending the monarchy and urging other people to join them, said Mr Somchai. He believes police already have a copy of the video clip as evidence.
Mr Somchai also called on the Foreign Ministry to seek cooperation from Japan -- where historian Pavin Chachavalpongpun and social critic Somsak Jeamteerasakul now live -- to track them down. Both Mr Pavin and Mr Somsak were seen speaking on Monday night via video.
The senator urged media to stop covering gatherings that violate the lese majeste law.