SAN FRANCISCO (Map, News) - City leaders expressed concern after a fatal tiger mauling Tuesday that the height of a wall around the San Francisco Zoo Lion House — which was supposed to protect visitors against such an attack — was about four feet lower than the minimum height recommended by the leading zoological association.

The day after a 350-pound Siberian tiger killed a zoo visitor and mauled two others, San Francisco Zoo Director Manuel Mollinedo originally said the wall was 18 feet tall with a 20-foot-wide dry moat. Thursday, however, he said investigators measured a significantly lower wall at 12 feet 5 inches tall. The Association of Zoos and Aquariums, which accredited San Francisco Zoo three years ago, publishes guidelines that say such walls should be at least 16.4 feet tall.

How the tiger escaped its enclosure is still a matter of investigation by numerous agencies, including the San Francisco Police Department and the USDA’s Animal and Plant Health Inspection Service.

The City could also face its second lawsuit in connection with a tiger attack at the zoo. An $8 million lawsuit in connection to the mauling of one of the same tiger’s handlers last year is in the court system.

In response to that lawsuit, the city attorney sent a letter to the victim’s lawyers, claiming that The City wasn’t liable for any injuries because the zoo has been leased and managed by the nonprofit San Francisco Zoological Society since 1993.

But one of the exceptions to releasing liability is if an injury occurred because of a “pre-existing condition” at the zoo. The big cat enclosure built in 1940 as part of a Depression-era government work project was owned and operated by The City for decades.

A City Hall legislative analyst on Thursday began researching information on big cat enclosures at leading zoos in the country, according to Supervisor Michela Alioto-Pier, who was among city leaders who said they would call for a variety of hearings and investigations when they next meet in early January.

“I’m particularly concerned by the discrepancy of the height of the wall,” said Supervisor Tom Ammiano

Jim Brownless, a spokesman for the federal Animal and Plant Health Inspection Service, said the zoo could be closed and employees could be sent to jail if such actions are found to be warranted.

Mollinedo said the zoo wouldn’t wait for the investigations to conclude before making immediate safety improvements, including new fencing, surveillance cameras and electrical wire around the perimeter, at the big cat enclosure. — Brent Begin and John Upton