The final traumatic moments of a girl, 10, killed after her mum 'invited strangers to rape her'.

WARNING: Graphic content.

The mother of a 10-year-old girl who was killed during a sickening sexual assault last month in New Mexico, USA, has told police she enjoyed watching her daughter being raped.

According to The Albuquerque Journal, Michelle Martens, 35, told police she had arranged encounters with at least three men who sought to sexually assault her daughter, Victoria, including one co-worker and two strangers she met online.

Victoria Martens.

The last was 31-year-old Fabian Gonzales. Along with Martens and his cousin Jessica Kelley, Gonzales now stands accused of playing a role the girl's death.

Police allege Victoria was made to consume methamphetamine before being sexually assaulted and strangled by Gonzales as Martens watched. Detectives believe Kelley, 31, then stabbed the girl, and she and Gonzales dismembered her body and set it alight in the bathtub.

The horrifying crime was discovered by police after Martens and Gonzales told neighbours they had been attacked by Kelley, and that Victoria was still in the apartment.

Police found parts of the school girl's body in a plastic bag in a laundry basket, and the floor of her bedroom was stained with blood.

Police Chief Godren Eden described the crime as "the most gruesome act of evil" he'd seen in his entire career.

It’s “a complete disregard of human life and betrayal by a mother,” he said, according to The Albuquerque Journal.

All three suspects have been charged with kidnapping, child abuse resulting in death, tampering with evidence, conspiracy, and contributing to the delinquency of a minor. Kelley and Gonzales are also charged with criminal sexual penetration of a minor.

Police have also seized a video camera, nine minidiscs, five smartphones, a USB, iPod, mobile phone, tablet and Kindle as part of the investigation, which could lead to further charges.

Co-accused, Fabian Gonzales and Jessica Kelley.

Martens - who is single - has another child by a different man, and neither he nor Child Services were aware of any previous incidents of physical or sexual assault of the siblings.

An attorney for the other child's father said he is both "saddened and sickened" by Victoria's death, and is seeking protection orders against all three suspects, should they be released, according the The Journal.

“The petitions he filed are based on the evidence released about Victoria’s murder as well as information his son has disclosed to him since the murder,” said his attorney Michelle Cortez in a statement to the paper.

It's unclear whether the boy was also assaulted, how long Martens had been arranging the encounters or if police have identified the other men she arranged to assault Victoria.