Detectives from PSNI Serious Crime Branch investigating the rape and murder of 23 year old Lorraine McCausland in North Belfast on March 8 1987 have today arrested four men.
Two men aged 54 and 56 were arrested in Belfast and two men aged 53 and 59 were arrested in Antrim.
They are currently in custody at Musgrave PSNI Station.
It brings the number of arrests to seven over the past two days.
Yesterday police detained two men, aged 49 and 56, in Scotland and another suspect, aged 53, in England.
Detective Inspector Michelle Griffin would appeal to anyone who has any information about this incident to contact Detectives on the non-emergency number 101. Alternatively, if someone would prefer to provide information without giving their details they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.