The mock hangings involved two blow up dolls, one with a Rangers scarf, the other with an Orange sash
Police have also set up a dedicated email address to gather video footage of disorder and vandalism at the game.
Toilets in the away end of the ground were vandalised and both clubs later released statements over fan behaviour.
Det Insp David Stewart, who is leading the investigation, said: "Today specifically, we are requesting people with mobile phone footage of vandalism within the toilets of the away support section to contact us.
"I would ask anyone who witnessed or who captured this vandalism to contact police, as it may assist with our enquiry.
"I understand there were a number of images and video shared online of this and I would be keen for people to contact us directly with any information they may have."
The detective added: "As part of the wider investigation, we have been viewing CCTV and obtaining footage from broadcasters in order to identify those responsible for disorder, vandalism and offensive or antisocial behaviour."
Police have urged anyone with footage or information to send it to the dedicated email address: CelticRangersDisorder@scotland.pnn.police.uk
A 27-year-old man has been arrested after effigies of Rangers fans were hung from the stands during the recent Glasgow derby at Celtic Park.