Police in California say the man killed by a tiger in a San Francisco zoo on Christmas Day may have died trying to save his friend's life.
Police say Carlos Sousa, 17, shouted in an attempt to distract the 300lb (136kg) tiger Tatiana as it clawed his friend Kulbir Dhaliwal.
The animal then killed Mr Sousa with a slash across his throat, allowing Kulbir and his brother Paul to escape.
The zoo has admitted that the wall around Tatiana's enclosure was too low.
Police are still investigating just how the four-year-old Siberian tiger escaped from her enclosure as the zoo was closing for the evening.
But city police chief Heather Fong distanced herself from reports that police believed the young men may have taunted or provoked the tiger.
She said there was no evidence anyone had dangled a leg through a rail into the tiger's enclosure.
Instead, police said the two friends were trying to save Kulbir Dhaliwal's life as the tiger clawed and bit him.
Trail of blood
When the tiger turned its attention to Mr Sousa, the two brothers, aged 23 and 19, ran towards a cafe, where they apparently hoped to find help.
After killing Mr Sousa the tiger then followed the trail of blood the Dhaliwals left.
Police shot it dead as it loomed over one of its victims before it could finish him off.
The Dhaliwals were both badly wounded but are expected to make a full recovery.
Mr Sousa's father, Carlos Sr, is quoted as saying: "He didn't run. He tried to help his friend, and it was him that ended getting it the worst."
Tatiana attacked one of the zoo's keepers last year
Zoo director Manuel Mollinedo says it is becoming increasingly clear that the tiger must have leaped or climbed out of its enclosure.
And he admitted that that the wall around it measured 12.5ft (3.81m), and not 18ft (5.5m), as he previously said.
The main accrediting agency for United States zoos recommends that the minimum height for walls at a tiger exhibit should be 16.4ft (5m).
But Mr Mollinedo said the enclosure had passed safety inspections without meeting any objections.
"Obviously now that something's happened, we're going to be revisiting the actual height," he added.