This article is about an (now) ex-nurse that was charged with first degree murder of residents in several nursing homes over a seven year time span. The ex-nurse is said to have quit multiple jobs without any provided reason, and to have had alcohol issues. The article also mentions her splitting with her husband before one of her jobs.
From a Kantian perspective, this woman treated people as a means. It is not clear as to what exactly she wanted to obtain from this, but the people she (maybe) murdered were not viewed as humans who are worthy of dignity and respect.
Kantian ethics also states that a person is a rational being. Rational being someone who can exercise sound judgement. In the case of murder, most would agree that killing someone without justification, and implication of defense (current or future), is rather irrational. While there was no mention of the reasons she may have (maybe) committed those crimes, we can assume that it started with the separation of her and her husband, and then escalated more with alcohol.
So, according to Kantian ethics, this woman is not a human because she is not behaving in a rational manner.