That is a big mystery... only Tina and Cooper know what happened to that money..
IMO, it is even possible that Tina didn't hand back the money.
Her story never really made sense to me.
To be humorous... Tina asks for some money.
Cooper hands her "one package".
She claims she handed it back telling Cooper she was not allowed gratuities.. citing a later incident when all stews were offered the tip money.
Then right before they launch that big search in March, a short comment pops up in her local paper claiming Cooper offered her money but she refused.. The only inside case info coming out publicly from Tina.. It sounds like she was front running the search in case the money was found and some was missing..
Can't prove it but the entire thing is suspicious.
This was undisclosed case info,, she did not publicize any other case info.. She also lied,, she asked for the money.