In a troubling report, one female lion from the Dallas zoo is left dead following an altercation with a male lion.

In a troubling report, a female lion from the Dallas zoo is left dead after being attacked by a male lion.

The incident unfolded in front of traumatized zoo visitors. One eyewitness to the ordeal stated “At first you think they're playing, and then you realize he's killing her, and ... you're watching it and you just can't believe your eyes.”

The 5-year-old lioness died almost immediately according to zoo authorities but they failed to explain how and why the vicious attack occurred. The female lion was reportedly held down by the other animal for about 10 minutes before she stopped moving.

The exhibit was closed after the killing. The male was removed along with three other surviving lions that had also been in the enclosure at the time of the incident. According to the vice president of animal operations and welfare at the facility, the group of lions had all been born in captivity and lived together at the zoo for three years prior to the attack.

Zoo workers are describing the traumatic incident as very rare. For now, the Dallas zoo plans on separating the male lions from the females.