The father of a young man who died after taking drugs has called for action after five deaths in Belfast in recent days.
A man passed away suddenly last Friday, while three young men and a teenage girl died suddenly on Monday.
The PSNI said they suspect a link with drugs in two cases, and said it is a possibility in the others.
The youngest was a 16-year-old girl from west Belfast.
Also among the dead are a 25-year-old father-of-one and a 26-year-old also from west Belfast, as well as a 28-year-old man who died in the Utility Street area of south Belfast.
Police officers believe that prescription and illegal drugs, taken with alcohol, are behind at least two of the tragedies.
Belfast man William Burns, who lost his son Jamie through drugs last November, says he understands the pain the families are going through.
He will launch a campaign on Monday, called 1 Pill Will Kill, to raise awareness of the dangers of drugs.
"I want to send my condolences from the Burns family to all of the five families who have lost a member of their family; believe me I know how you feel right now", he said.
"Nineteen weeks ago my son took one pill on a night out and died."
While a drugs link has not yet been confirmed by the PSNI in the deaths, Mr Burns says Belfast needs to say "enough is enough."
"Surely to God, if this doesn't make some people wise up then I really am wasting my time here - five people have died, not one but five", he added.
"At some point we as a city need to say enough is enough. We seem to be at a crossroads here.
2The PSNI can only do so much. Drug agencies can only do so much. Most of us bury our heads in the sand unless it affects our families - and I'm not afraid to say that was me up until my Jamie died - or we can begin to fight back."
Mr Burns has urged anyone aware of drugs or drug dealing to alert Crimestoppers and to get involved in anti-drugs initiatives.
"Next time there's a drug death - and believe me there will be - it might be someone you know or a member of your family", he said.
"Then you will want to help but it will be too late for them. Don't make the same mistake I made.
"Just because drugs haven't come to your door yet, don't wait until they do before you make a stand against them."
Earlier this week Detective Chief Superintendent Tim Mairs said there had been an increase in the number of drugs-related deaths. From January to November last year there were 78 deaths in Northern Ireland - a 28% increase on 2015.
Mr Mairs added that tackling drugs remained a priority for police and pointed out that during the recent Operation Torus - which ran from February 27 to March 26 - officers seized more than £793,000 worth of drugs and conducted 389 searches resulting in 92 arrests.
Police charged or reported 74 people to the Public Prosecution Service.
Meanwhile, the funeral of the youngest of Monday's victims, the 16-year-old girl, is set to take place in west Belfast today while the 25-year-old man will be laid to rest tomorrow as will the 26-year-old man at different Requiem Mass services also in west Belfast.