A lioness killed her longtime mate at the Indianapolis Zoo earlier this week. Zoo officials learned of the incident when they heard an "usual amount of roaring" coming from the lion enclosure on Monday morning. When they went to check on the noise, they found lioness Zuri holding the male lion Nyack by the neck.  

"Zoo personnel made every effort to separate the lions, but Zuri held Nyack by the neck until he stopped moving," the zoo said in a statement shared by CNN. Nyack was the father of three of Zuri's cubs and were living together for eight years.

"Our Zoo family is sad to announce 10-yr-old male lion Nyack has died. Earlier this week he was injured in a physical incident with female lion Zuri. We will conduct a thorough review to attempt to understand what may have led to this. Nyack was a magnificent lion & will be greatly missed. We appreciate the support from our community as we cope with the loss," the zoo wrote on Twitter in their official statement on Friday.

The staff are unsure what sparked the incident and have been investigating it. The grisly scene happened before the zoo was open to the public.