(NEW YORK) -- Twelve squirrel monkeys that were stolen from Zoosiana, a Louisiana zoo, shortly before midnight Saturday remain missing five days later.
The thief targeted facilities of smaller primates and "compromised" the squirrel monkey exhibit, successfully stealing 12 from the enclosure, according to zoo officials.
The person who broke into the zoo first tried to gain access into the marmoset habitat, another small monkey, but was unsuccessful. The marmoset escaped its enclosure and was later caught by the zoo, George Matthew Oldenburg, the owner of Zoosiana, which is located in Broussard, told ABC News in an interview.
The person then headed for the squirrel monkey exhibit and broke into the main house where monkeys sleep. There were 38 monkeys in that habitat, 12 of which were stolen, Oldenburg said.
The thief evidently brought tools to cut the wire, break locks and destroy the enclosure. It appears the monkeys were taken in a burlap sack as one was left behind at the scene, Oldenburg said.
Oldenburg said the zoo does not know what happened to the monkeys and is very concerned about them because they are exotic animals and on a special diet. He is also worried that the thief may not be skilled enough to recognize if one of the monkeys is not healthy.
"People think monkeys eat bananas, that's all you have to feed them, but no they are not going to survive on that," Oldenburg said.
Oldenburg also said the theft was stressful on the animals that were not taken and was worried about their well-being, saying it was "cruel" and this kind of stress level could cause them to die.
"I'm angry that these were taken from me but I want to make sure that my animals were maintained and cared for properly," Oldenburg said.
The remaining squirrel monkeys were assessed by the zoo's veterinarian and animal care team and there are no apparent issues affecting their health or well-being, Zoosiana said in a statement posted on Facebook.
The remaining monkeys were afraid of going into their night house for a while after the break-in, according to Oldenburg.
"All other animals are accounted for and appear to have been undisturbed," Zoosiana said.
Oldenburg is hoping the monkeys will be recovered, but said it is unlikely. In the meantime, security at the zoo will be increased.
The zoo was closed on Sunday, but Zoosiana said this was due to weather and was unrelated to the theft.
An investigation into the incident is ongoing. Zoosiana said it is working with local, state and federal agencies.
Police told ABC News that they are in the process of going through surveillance footage, even going back a few days before the incident to see if a suspect or suspects appear in footage.
While there are cameras in the zoo, Oldenburg said there was not any identifiable information that could point to a suspect. Oldenburg is hoping someone will come forward with information about the monkeys' whereabouts.
He had one message for the thief. "Shame on them," Oldenburg said.
The incident at Zoosiana comes as the Dallas Zoo faces a series of suspicious incidents. In the most recent incident, two emperor tamarin monkeys were stolen from their habitat earlier this week.
The Dallas Police Department found the monkeys safe on Tuesday. No arrests have been made and the investigation is still ongoing. There's no known connection to the monkeys stolen at Zoosiana.
As of now, there is no indication that there is a connection between the Texas and Louisiana zoo break ins, according to the Broussard Police Department.
In January, a clouded leopard escaped her enclosure at the Dallas Zoo after the fence of her habitat was "intentionally cut," the leopard was found the same day it went missing, according to officials. A second fence inside the zoo's langur monkey habitat was cut although no monkeys escaped or were danger or harmed.
The Dallas Zoo also found a rare and endangered vulture dead in its enclosure in January, with officials saying it did not appear to have died from natural causes.
Dallas Zoo is offering a $25,000 reward for information that leads to the arrest of those responsible for the incidents.