公安人员审问四名窃贼嫌疑犯。已知，这四人当中仅有一名是窃贼，还知道这四个人中每

人要么是诚实的，要么总是说谎的。在回答公安人员的问题中2

甲说"乙没有偷，是丁偷的。"

乙说"我没有偷，是丙偷的。"

丙说"甲没有偷，是乙偷的。"

丁说"我没有偷。"

请据这四人的答话判断谁是盗窃者。-Four police officers interrogate suspects thieves. Known, the four of them only a thief, but also know that four out of every

People are either honest or always lie. In answer to the question of two police officers

A says "B did not steal, steal Ding."

B said, "I did not steal, steal is propylene."

Propionate said, "A not steal, steal a B."

Ding said, "I did not steal."

Please answer according to which four of the judge who is the thief.