(CNN) A lioness killed the father of her three cubs at the Indianapolis Zoo this week.

In a statement Friday, Indianapolis zoo staff said they heard "an unusual amount of roaring" at the lions' outdoor yard early Monday morning.

When they arrived, they saw a female lion, Zuri, in a physical confrontation with their adult male lion, Nyack.

"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.

Zoo veterinary staff conducted a necropsy on Nyack and found that the 10-year-old male died of suffocation from injuries to the neck.

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