SACRAMENTO, Calif. (AP) – Sacramento Zoo officials say a Sumatran female tiger was killed by her mating partner after the two felines were put in the same enclosure for breeding.

The zoo says in a statement the male tiger became aggressive with the 15-year-old Baha minutes after a physical introduction Wednesday morning.

Officials say staff monitoring the introduction from outside the enclosure used a water hose and fire extinguishers to separate the animals. Once the male tiger was secured, veterinarians rushed to help Baha, but she had already died.

They say that since arriving at the zoo on December 2015, the 12-year-old Mohan had had visual contact with Baha. Staff decided to physically introduce the tigers on Wednesday.

Baha had been at the Sacramento Zoo since 2002 and had successfully bred with three other partners, giving birth to five offspring.