The serial killer who abducted, raped and murdered four women in California between 2013 and 2014 has spoken out from prison for the first time.

In a DailyMail.com exclusive clip, Steven Gordon admits that what he did is 'beyond evil' and the slayings were 'screwed up'.

He was sentenced to death in December 2016, after telling the judge he deserved to die for his crimes.

Now he lives with what he did every day by reading a letter his niece wrote him, where she called him disgusting.

In the interview with Dateline NBC's Keith Morrison from death row, that will air in full on Friday, he said: 'It's beyond evil, what happened.'

When asked what his family thought about the results of his trial, Gordon said they were 'obviously not very happy about what happened.'

The death row inmate then described a letter he received from his niece, that hangs on the wall of his cell.

'I love my niece more than anything,' he said. 'She just said, "How could you do that to four women? You guys are evil. You're disgusting,"' he said. 'It was pretty bad.'

Gordon and another sex offender, Franc Cano, 30, were wearing GPS tracking devices for prior offenses when they allegedly worked together to randomly target the women in 2013 and 2014.

While Gordon has been convicted and sentenced to death, Cano will go on trial for the murders later this year.

The women raped and murdered were Jarrae Nykkole Estepp, 21, of Elk City, Oklahoma; Kianna Jackson, 20, of Las Vegas, and Martha Anaya, 28, and Josephine Monique Vargas, 34, both of Santa Ana, California.

Gordon (L) and another sex offender, Franc Cano (R), were wearing GPS tracking devices for prior offenses when they allegedly worked together to randomly target the women

The body of Jarrae Nykkole Estepp (L), 21, from Elk City, Oklahoma was found on a conveyor belt at a recycling centre in Anaheim, which prompted the initial investigation; Kianna Jackson (R), 20, of Las Vegas, was also raped and murdered

Martha Anaya (L), 28, and Josephine Monique Vargas (R), 36, both of Santa Ana, California, were also raped and murdered in 2013 and 2014

The body of Estepp was found at a recycling plant while the remains of three other women have not yet been found.

Gordon had previously said that he deserved to die for what he did, and that he fired his public defender and represented himself to make the process go more quickly, as reported by the Los Angeles Times.

In the exclusive clip, Gordon admitted to Morrison that he's kept that letter from his niece.

'I read it periodically to keep my mind focused that I screwed up,' he said.

'Is screwed up the right expression?' Morrison asked.

'Probably not,' Gordon said. 'I just didn't want to say what I really think.'

'Well, why don't ya?' Morrison asked.

'What me and him did was beyond evil,' Gordon said.

The body of one of the women, Jarrae Nykkole Estepp, was recovered from Anaheim's Republic Waste Services in March 2013, which sparked the initial investigation

Gordon confessed during grand jury proceedings, giving graphic details about picking up the women in his car with another registered sex offender and raping them, but the confession was excluded from evidence; Gordon is seen here in his interview with Dateline to air Friday

Gordon confessed during grand jury proceedings, giving graphic details about picking up the women in his car with another registered sex offender, raping them behind an Anaheim paint and body shop where the men camped, and killing them, authorities said.

But the confession was not allowed at trial.

The judge excluded it because Gordon told police he didn't want to talk before launching into the elaborate account of the killings, Orange County Deputy District Attorney Larry Yellin said.

At one point Gordon blamed those responsible for monitoring his whereabouts for the women's deaths.

He claimed if they had kept him from associating with Cano that the four victims would still be alive, according to the Los Angeles Times.

The night Estepp died, a message from Gordon's phone to Cano's read: 'This is the best one yet.'

DNA samples from Estepp's body matched Cano's and Gordon's genetic material, authorities said.

Gordon (R) is seen here appearing for his arraignment with associate defender Denise Grag(L) during a hearing in superior court in Santa Ana, California in October 2014

Authorities believe Cano and Gordon have known each other since at least 2010, when Cano cut off his GPS device and fled to Alabama, where the men were arrested.

In 2012, they cut off the devices again and took a bus to Las Vegas using fake names.

They were arrested two weeks later.

Both men are registered sex offenders and were convicted in separate cases of lewd and lascivious acts on a child.

The full one-hour report will include more from Gordon, as well as interviews with the mothers of the four victims and Detective Julissa Trapp.

The special will air Friday at 10.00pm Eastern, 9.00pm Central on NBC's Dateline.