Dallas Zoo making 'significant changes' to security

The Dallas Zoo says it knows it needs to make "significant changes" to its security following multiple incidents where someone intentionally tampered with animal habitats.

"Although our security program had worked in the past, it has become obvious that we need to make significant changes," the zoo said in a statement. "Words cannot express the frustration our team is feeling."

READ MORE: Dallas Zoo: Timeline of suspicious events that police are investigating

The Zoo increased security patrols, and added overnight staffing and cameras after a clouded leopard escaped from its enclosure on Jan. 13. Police say the animal escaped through an intentional cut in the habitat.

It was discovered the langur monkey exhibit had also been cut.

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Nova (Source: Dallas Zoo)

On Jan. 22, a 35-year-old endangered vulture was found dead in its habitat after sustaining a "wound."

Despite the additional security, the Zoo announced two emperor tamarin monkeys were missing on Monday. Dallas police believed the monkeys were stolen, they were later recovered at a home in Lancaster.

READ MORE: Dallas Zoo monkeys found in Lancaster church's community house

The Dallas Zoo says they have consulted with security experts to figure out the best way to secure its 106-acre space.

"Securing a zoo is a unique challenge that requires specific needs because of the environment; there is often extensive tree canopy, expansive habitats and behind-scenes-areas to monitor, and heavy traffic from guests, contractors, and staff," said the zoo in a statement.

Cameras have been added to the areas the zoo considered "challenging."

The Dallas Zoo also says it has added additional fencing and will continue to expand new security measures.

"Our security personnel, staff, and volunteers all already undergo background checks. The Zoo is evaluating our internal policies and identifying additional partners with whom we will work to further strengthen security measures to protect the Zoo, our animals, our staff, our guests, and our community," said the zoo in a statement.

No arrests have been made in connection to the events at the zoo.

Dallas police and U.S. Fish and Wildlife are investigating to see if they are connected.

The zoo is offering a $25,000 reward for any information that leads to an arrest and indictment, and asks anyone with information to call 214-670-7694.