You see, xylitol breaks down in a very predictable way.

木糖醇的分解非常有规律
And when measured in concentrated levels,

当进行浓度分析的时候
it can give me a very specific timeline.

可以很轻易地算出停留时长
Think of this gum,

想象一下这颗口香糖
when chewed, as a... as a body decomposing.

它被咀嚼时正如尸体在腐烂
Oxygen dissipates, muscles stiffen at a certain rate.

氧气耗尽肌肉以一定的速率僵化
That's what gives us the time of death.

这些是我们推测死亡时间的依据
In your case,

在你这里
that's what gives us the, well... time of song.

这个口香糖让我们推测出了歌曲的长短
The last few particles that I found in that microphone

我们在麦克风里找到的最后这几颗小颗粒
put you at the crime scene during the time of the murders, Arnold.

证明了案发时你在现场阿诺德
So, here's what I think happened.

所以我觉得案发经过是这样的