Paolilla was born in 1986. Her father died when she was two and she had alopecia, wearing wigs from childhood; she had been badly bullied and had then, in her final years at Clear Lake High School, been taken up by a group of popular students, among them Tiffany Rowell and Rachael Koloroutis.
On July 18, 2003, she and her boyfriend Christopher Snider went to Rowell's house in Clear Lake, near Houston. Four people were shot dead: Tiffany Rowell, eighteen; Rachael Koloroutis, eighteen; Marcus Precella, nineteen; and Adelbert Sanchez, twenty-one. Two were also beaten. The house was not robbed of anything significant. The Texas press called her the Psycho.
The case went unsolved for three years. Paolilla married, became addicted to prescription opioids, and in 2006 talked about the killings to people around her; one of them contacted the police. Snider killed himself in 2006 before he could be charged.
She was convicted of capital murder in 2008 and sentenced on October 14, 2009 to a term with parole eligibility after forty years. A retrial was ordered on appeal and she was convicted again in 2015.
No settled motive emerged. The prosecution suggested drugs and jealousy; her account varied. The entry records that the four dead were her friends, that she was seventeen, and that nothing in the case explains it.