The Progressive Unionist Party leader has warned that loyalist paramilitaries may take the law into their own hands over the Lisa Dorrian murder.
Lisa Dorrian's body has never been found
David Ervine said he feared that unless the police caught her killers loyalists could take action themselves.
The UVF and the Red Hand Commando have been "investigating" her disappearance.
He said: "The more they think justice is not likely to happen in that respect the more they're going to, in their own minds, protect their community."
Mr Ervine, whose party is close to the UVF, told the BBC's Spotlight programme that would probably mean killing those they suspected of the murder.
"Much as that is distasteful, much as people wish it wouldn't be the case," the east Belfast assembly member added.
PUP leader David Ervine said loyalists may take action
Lisa, 25, disappeared after a party at a caravan site in Ballyhalbert in County Down on 28 February.
Her body has never been found. Three men were questioned about the killing but were later released.
The police are looking at the possible involvement of members of the Loyalist Volunteer Force.
Her mother, Pat, also told the programme, broadcast on Tuesday, she would talk to mainstream loyalist paramilitaries if it meant getting her daughter's body back.
When asked whether she wanted "paramilitary justice", Mrs Dorrian said she did not.
She added: "If they can help, I would be really grateful".
The family is offering a £10,000 reward for information leading to the recovery of Lisa's body.
Graffiti in the area following her disappearance suggested a link between the case and the LVF.
When she disappeared, Lisa, a shop assistant, left her handbag and personal belongings behind her at the caravan park.
A caravan from the site was removed for examination.