Why did Melissa Huckaby kill Sandra Cantu?

Huckaby may be the only person that would know for sure but it seems to be a sexually motivated killing. What makes it so unusual is because Huckaby is a woman. Most women that kill tend to be caregivers or at least for profit. Huckaby fits neither of these.

Although Aileene Wurnos was compared to male serial killers, there is no indication that her crimes were sexually motivated. Wurnos needed her victim's money and cars. The easiest way to get what she wanted was to murder. In this respect, she does fit the mold of female serial killer.

Huckaby does not quailify as a serial killer for the fact that she got caught before she could kill again. But the sexual conotations makes her atypical.