That was until they got a call.
"While we were setting up a plan to start an area search of the zoo, we got a call from Newport Beach police," Santa Ana police Cpl. Anthony Bertagna told KNBC.
Stealing a lemur is actually a federal crime. Lemurs are an endangered species, Bertagna told KNBC.
"It sounds more like at this point that it was some kind of prank or a challenge because they placed (the lemur) in a public area in a secure box with a note," Bertagana told KNBC.
The animals are all secure in the zoo and are OK after their ordeal.