Calcutta, Dec. 16 :    Calcutta, Dec. 16:  In a replay of an incident that took place nearly five years ago, an apparently drunk man dodged security, clambered over the wire fence of the tiger enclosure at the Alipore zoo, swam across the moat and then tried to 'entertain' a tiger till it mauled him to death. In January 1996, two drunk men straight from a New Year's-eve bash had entered tiger Shiva's enclosure and tried to garland him. The terrified tiger had killed one of the men instantly and seriously injured the other. At 4.30 this evening, as the guards at the zoo were preparing to close for the day, a 30-year-old man, as yet unidentified, tottered across to the tiger enclosure where nine-year-old Bob was pacing the ground. As the stunned visitors watched, the man clambered over the wire-fencing and dived into the 20-feet deep moat. Paying no heed to the cries of the securitymen who had spotted him by then, he determinedly swam towards the tiger, who suddenly seemed to take an interest in the figure rapidly approaching him. Pulling himself out of the water as he reached the second protective fencing around the enclosure - a precaution taken after the Shiva incident - he prepared for the final assault. As visitors gasped at this 'incredible sight', he heaved himself over the fence and within seconds was face-to-face with Bob. He first gesticulated at the tiger, making faces at him and mouthing words that could not be heard. Then, as a hush descended around the enclosure, he tried to embrace Bob in an apparent display of friendship. It was at this moment that the tiger, tense at an unknown figure approaching him, reacted. He lunged at the man, hitting him hard with his paws and throwing him to the ground. Then Bob dug his teeth into the nape of the man's neck, shaking him violently. By now the keepers at the zoo had got into the act. They quickly got on to the top of the cage from where two other tigers, Uday and Shweta, were keenly watching the 'show', and pulled up the hatch. This seemed to come as a relief to Bob who left the man and quietly walked into the cage. By the time the man was rushed to SSKM hospital, he was dead. 'I wish I had not come to the zoo today,' said Tapan Bose of Kankurgachi, who witnessed the incident. 'It was so ghastly that the sight is going to haunt me for many nights. I just turned my face away as blood started spouting from the man's neck.' Alipore zoo director Adhir Das said it was just fright that led Bob to kill the man. 'It was because of this that he repeatedly attacked him on his chest, neck and belly,' he said. He added that the man was 'intoxicated' and had probably jumped into the cage 'to commit suicide'. Deputy commissioner of police (port), Zulfikar Hassan, who rushed to the zoo after the incident, said a case of negligence had been registered against the zoo authorities. 'But our first priority is to identify the man and determine whether this was a drunken act or whether he really wanted to commit suicide,' Hassan said. There have been a number of attempts to enter animals' enclosures in the Calcutta zoo. Soon after Shiva killed his 'visitor', a woman entered the crocodile pit to collect coins in February 1996. In May 1999, a man climbed on top of the tiger enclosure gate. He was arrested.