题目内容：
根据以下材料回答第 1～4 题：In 1968，five people were murdered in Northern California．The killer called himself the Zodiac．He either shot or knifed his victims．No one knew when，where，or who the Zodiac would kill next．
Paul Stine is believed to have been his final victim．Stine was a cab driver in San Fran--cisco when he was shot to death in l969．The Zodiac sent a piece of Stine’s bloody shirt to a newspaper bragging about the killin9．
The Zodiac has been compared with the recent Washington，D．C．snipers．These se－rial killers seemed to have no reaon for the murders．Victims were chosen at random．Let—ters were sent to newspapers．In the letters，the killers made fun of the police who
tried to catch them．Both the Zodiac and the D．C．sniper got thrills out of murdering and scaring people．
Arthur Allen was thought to be the Zodiac．The police never charged him．He denied
that he had done the murders．When Alien died in l992，tests were done on his body．Partof his brain tissue was tested／or DNA．His DNA Wasn’t the same as the DNA on thestamp of a letter sent by the Zodiac．The results proved that Allen had told the truth and was not the Zodiac．
Althought the killings stopped in 1969，the Zodiac wrote letters until 1947．It has been thirty--three years since the murders．Over 2500 tips have been given to the police．Most of the old detectives have retired．Kelly Carroll,a police investigator，keeps cheeking out new clues with the aid of new technology．Still no one knows if the Zodiac is dead or alive or how many people’he killed．
When the Zodiac killed，he got ．
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