Sounds like an eye for an eye. Torture for torture. Granted, Pike herself was raped and abused in her youth, but not an excuse.

From Wikipedia: According to court testimony, for the next 30 minutes, Slemmer was taunted, beaten, and slashed. During the attack, Slemmer begged for her life. Shipp used a box cutter to carve a pentagram into her chest while she was still alive, while Christa used a meat cleaver. Finally Pike smashed Slemmer’s skull with a large chunk of asphalt, killing her. Pike kept a piece of Slemmer’s skull, and would show it off and boast about how she got it.