In the early hours of Sunday (May 27) the Portsmouth, U.K. police department reported that two people died after falling ill at the Mutiny Festival site in King George V Playing Fields, Cosham. The festival, which was initially planned to last through the weekend, was canceled following the deaths. Three men were taken into police custody on the suspicion that they were involved in the supply of Class A drugs.

On Saturday (May 26) night, the festival account tweeted a “harm prevention alert,” telling the public that they had been made “aware of a dangerous high strength or bad batch substance on site.” The statement continues, “We strongly urge you to not take any substances whatsoever and to report any symptoms of illness / discomfort immediately to medical, welfare, security or the safeguarding team.”

Festival organizer Luke Betts told Billboard that Mutiny became aware of the substance after some festival goers became ill on Saturday.

Harm prevention alert

Festival family – we are aware of a dangerous high strength or bad batch substance on site.

We strongly urge you to not take any substances whatsoever and to report any symptoms of… https://t.co/8r2Merf66g

— Mutiny Festivals (@MutinyFestivals) May 26, 2018

While illegal substances are listed under the festival website’s “prohibited items” section, it was confirmed that the two deaths — Georgia Jones, 18, and Tommy Cowan, 20 — were both drug-related by their respective parents. However, the official cause of death has yet to be released by the police. The two deaths are currently being treated as separate and unsuspicious. According to Betts, both were treated by emergency first aid teams at the festival until paramedics arrived to take them to the Queen Alexandra Hospital.

Jones and Cowan were only two of 15 individuals from the Mutiny Festival to be hospitalized on Saturday night. A representative of the Queen Alexandra Hospital confirmed to Billboard that those who were admitted to the hospital were treated for a range of issues and were not all drug-related. Several were treated for symptoms related to alcohol intoxication, and others were assault-related.

In the past, Mutiny Festival has run into safety issues. The News, Portsmouth reported that behavior at last year’s festival resulted in the Portsmouth community banding together in order to demand an age restriction. Their report states that a 13-year-old boy was found a short distance from the grounds and admitting to taking nitrous oxide, cannabis and alcohol. He, among other festival goers, was also a victim of assault. Billboard has reached out to the Portsmouth police for a comment.

The 2018 festival — which was also the fifth anniversary of Mutiny’s creation — took precautions in order to avoid safety hazards, including the enforcement of an age restriction. Although 16- and 17-year-olds were still allowed to attend the event, they were required to buy a special “Teen Ticket.” According to the “Terms & Conditions” page on the Mutiny Festival’s website, “Teen Ticket” holders were required to show a valid form of identification and provide basic details (such as name, date of birth and home phone number) to the festival management team in order to gain entry into the festival. There was also an entrance provided for “Teen Ticket” holders, separate from the main entrance.

Of the festival security, Betts said: “Our crowd management and security specialists, Vespasian, liaise extensively with Hampshire Constabulary and other authorities in preparations for the event. Their crowd control and security team on Saturday totalled 175 against the requirement of 155.” On the day of the event, police were working alongside the Security Industry Authority licensed team “to manage access and searches on the gates.” In addition, three drug dogs were present at the gates — all of which were monitored by CCTV.

The three men suspected to be involved in the distribution of Class A drugs are still in police custody. The police supported Mutiny’s decision to cancel the remainder of the festival, both out of respect for those affected by the tragedy and as a way of protecting other festival-goers from harm. Craig David, who was scheduled to appear, also showed his support in a tweet: “My heart goes out to the family and friends of the two young people who lost their lives at @MutinyFestivals yesterday.”

My heart goes out to the family and friends of the two young people who lost their lives at @MutinyFestivals yesterday.❤

— Craig David (@CraigDavid) May 27, 2018

The Portsmouth police department is currently encouraging anyone in the UK with information that could potentially be useful to their investigation to reach out and call 101.

This story originally appeared on Billboard.