帮忙看看,这句话是不是应该这样理解：但这些信息没有被公众.因此,只有杀手才知道真实的杀人武器是哪件

帮忙看看,这句话是不是应该这样理解：但这些信息没有被公众.因此,只有杀手才知道真实的杀人武器是哪件
中文出版物的具体翻译
but that information had been kept from the public. Thus, only the killer would know which object was the real murder weapon. ——————〉但这早已是众所周知的了,这名嫌疑人自然也知道
上下文具体内容如下,
The man sat stoically at one end of the table, carefully crafting his replies to the FBI agent’s inquiries. He wasn’t considered a major suspect in the murder case. His alibi was believable and he sounded sincere, but the agent pressed on nevertheless. With the suspect’s consent,he was asked a series of questions about the murder weapon:
“If you had committed this crime, would you have used a gun?”
“If you had committed this crime, would you have used a knife?”
“If you had committed this crime, would you have used an ice pick?”
“If you had committed this crime, would you have used a hammer?”
One of the weapons, the ice pick, had actually been used in the commission of the crime, but that information had been kept from the public. Thus, only the killer would know which object was the real murder weapon. As the FBI agent went down the list of weapons, he observed the suspect carefully. When the ice pick was mentioned, the man’s eyelids came down hard and stayed down until the next weapon was named. The agent instantly understood the significance of the eyelid behavior he had witnessed, and from that moment forward the “minor” suspect became the primary person of interest in the investigation.He later confessed to the crime.
坐在桌子另一端的那个男人小心谨慎地回答着联邦调查局特工的问题.其实,当时他还不是那次谋杀案的主要嫌疑人,他有充分的证据证明自己不在现场,言辞也很真诚,但是那名特工却依然不停地问问题.经当事人同意,现将关于凶器的部分提问公布如下：
“假如你参与这宗案件,你会使用枪吗?”
“假如你参与这宗案件,你会使用刀子吗?”
“假如你参与这宗案件,你会使用碎冰锥吗?”
“假如你参与这宗案件,你会使用锤子吗?”
这里所说的碎冰锥便是本案的作案工具,但这早已是众所周知的了,这名嫌疑人自然也知道.这位特工的主要目的其实是想观察嫌疑人在听到这些凶器的名字时的反应.当他提到碎冰锥时,那名男子的眼皮明显地耷拉了下来,而且一直耷到下一种凶器的名字出现.这位特工立刻明白了其中的意义.从那一刻起,这名嫌疑人就成为了该案件的第一嫌疑人.后来的进展说明他没有被冤枉.

你的理解是对的,不过
had been kept from the public
和
had not been revealed to the public
意思一样,即
没有向公众披露 .
所以句子的一个适当的翻译是
但这些信息没有向公众披露,因此,只有杀手才知道真实的杀人武器是哪件