18-year-old Jonathan Cairns was murdered 20 years ago but his killer(s) still remain at large
The women were arrested in the Derry area on Thursday as part of the police probe.
The 18-year-old was attacked and murdered on his way home in Ballykelly after a night out and his body was buried in a shallow grave in a local forest.
A number of other people were arrested last year over his murder and were also released on bail.
