A young woman, Dianna Hanson, has been mauled to death by a male African lion while working as a volunteer intern at a private animal sanctuary near Fresno in Central California.

Dale Anderson, founder and executive director of the Cat Haven sanctuary, confirmed the 26-year-old intern was killed by a lion (named Cous Cous) when she entered the enclosure. However, he refused to divulge any more information.

Cous Cous, the Lion
Cous Cous, the lion, mauled a young woman to death on 7 March, 2013 Cat Haven

Anderson, visibly shaken by the event, said in a written statement: "We take every precaution to ensure the safety of our staff, animals and guests."

A spokesman for the Fresno County Sheriff's Office, Lieutenant Robert Miller, said authorities found Dianna Hanson inside the lion's enclosure, severely injured. They tried to distract the lion and lure it to an adjoining pen in order to enter the enclosure and provide medical attention to the unconscious intern but to no avail. Eventually, the deputies had to shoot the lion in order to get inside the enclosure and rescue the intern.

Investigators are still trying to determine the reason why the intern entered the lion's enclosure and what might have provoked the attack. The private zoo is normally closed on Wednesday and only one worker was present at the time of the lion's attack.

The four-year-old lion had been nurtured at Cat Haven since it was a cub, said Tanya Osegueda, a spokeswoman for Project Survival - the non-profit organisation responsible for operating the private animal sanctuary.

Cat Haven was founded in 1993 on a 100-acre site west of the King Canyon National Park. The private zoo, located in central California, has housed several big cats, including lions and leopards. The last 13 inspections by the US Department of Agriculture showed no violations committed by the private zoo. The most recent inspection was carried out on 4 February. Cous Cous was one of two lions nurtured by the private zoo. The zoo's licence allows it to keep 47 animals and around 28 are resident at the present time.

Nicole Paquette, vice president of the Humane Society of the United States, slammed the zoo authorities' callousness.

She said: "[The intern] should never have been in the enclosure with him. These are big cats that are extremely dangerous, and they placed the volunteer in the actual cage with a wild animal. That should have never happened."

According to Big Cat Rescue, there have been 21 deaths (16 adults and five children) and an additional 248 adults and children have been mauled since 1990. However, they wee quick to caution readers, saying the numbers might not be accurate because of the lack of an official reporting agency for such cases.