Blue tablets which left 14 people needing emergency hospital treatment in Fort William are still being used, police have warned.
Emergency warnings were issued by police and health experts after people suffered extreme reactions at the weekend after taking what they believed were Valium tablets.
Fourteen people, mostly aged between 19 and 24, were admitted to the town's Belford Hospital for treatment.
Northern Constabulary say that despite warnings people continue to use the dangerous tablets.
A spokesman said: "Police and medical staff at NHS Highland are repeating their warning to anyone who has obtained or has been offered tablets which are not prescribed to them by a doctor, not to take them."
A 22-year-old man was arrested on Sunday and charged with being involved in the supply of drugs. He was expected to appear at court on Monday but was released by the Crown.
A Crown office spokeswoman said: "After a full and careful consideration of all the facts and circumstances in this case, including all of the available evidence, the procurator fiscal instructed that he be liberated pending further enquiries."
Symptoms from the fake blue tablets include overheating, dizziness, sickness, headaches and unconsciousness.
Anyone with the tablets is urged to take them to the Fort William police station or Belford Hospital, or phone NHS 24 on 08454 242424.