The Indianapolis Zoo is trying to find out why a lioness had killed her boyfriend by suffocation.
The zoo announced that the lioness had attacked her 10-year-old companion in the courtyard on Monday before the park opened for the day.
The zoo said they had lived together for 8 years and had three cubs in 2015.
The Indianapolis Zoo borrowed the lion from the zoo in San Diego.
The park said her team heard unusual roar from the yard and tried to separate them, but the lioness grabbed her husband from the neck until he stopped moving.
An autopsy confirmed that the lion died of suffocation due to neck injuries.
The zoo stated that the daily records maintained by the staff in the past did not show any unusual aggression, injury or injury between the two.
