SAN FRANCISCO - Police radio transcripts from the night of a deadly tiger attack revealed a chaotic scene at the San Francisco Zoo as zookeepers struggled to sedate the animal and medics refused to enter until they knew they would be safe.

Zoo employees also initially questioned whether early reports of the attack Tuesday were coming from a mentally unstable person, according to an 18-page log of communications from police dispatchers to officers and emergency responders at the scene.

Sgt. Neville Gittens, a police spokesman, declined to comment beyond the transcript released late Friday. Authorities have not indicated that any delays hindered their response, and Police Chief Heather Fong has praised officers for their quick action and collaborative work with the zoo staff.

Zoo officials yesterday did not immediately return messages seeking comment.

The attacks killed Carlos Sousa Jr., 17, and seriously hurt two of his friends. Paul Dhaliwal, 19, and Kulbir Dhaliwal, 23, were released from a hospital yesterday.

The first report of an attack - a male bleeding from the head - came in at 5:08 p.m.

According to the logs, zoo personnel initially told police that two men reporting the escaped tiger might be mentally disturbed and making something up, though one was bleeding from the back of the head.

By 5:10 p.m., zoo employees reported that a tiger was loose. By 5:13 p.m., the zoo was being evacuated and locked down as Fire Department responders arrived at a zoo entrance. No one was allowed to go inside the zoo.

For several minutes, the medics refused to enter the zoo until it had been secured. Meanwhile, zookeepers were trying to round up what they initially believed to be multiple tigers on the loose and hit them with tranquilizers.

"Zoo personnel have the tiger in sight and are dealing with it," reads a 5:17 p.m. note on the transcript.

The transcript does not indicate when police or emergency responders entered, but by 5:20 p.m. medics had found one victim with a large puncture to his neck. The tiger was still loose.

As medics attended to the victim, an officer spotted the tiger sitting down before it fled and began attacking another victim, according to the logs.

At 5:27 p.m., less than 20 minutes after the initial reports, the officers began firing, killing the 350-pound Siberian tiger.

It was unclear whether letting police and medics into the zoo sooner would have altered the outcome of the attacks or subjected emergency responders to greater danger with a tiger on the loose.

Police said Friday that they had completed their investigation on zoo grounds, and that investigators had "found absolutely no evidence of an intentional release."

It has become increasingly clear that the tiger climbed over the wall of its enclosure, which at just under 121/2 feet high was about four feet below the recommended minimum for U.S. zoos.

Zoo officials said the zoo would reopen Thursday.

The zoo could face heavy fines from regulators and lose its license. It also could be hit with a huge lawsuit by the victims or their families.