Three people arrested in connection with the deaths of two teenagers who had taken the drug mephedrone have been released on bail, police said today.
The trio - males aged 26, 20 and 17 - were detained after the deaths of Louis Wainwright, 18, and Nicholas Smith, 19, in the Scunthorpe area on Monday after taking mephedrone during a night out.
The deaths have provoked a nationwide debate on what to do about so-called "legal high" drugs.
Police also arrested a fourth person - a 26-year-old man - who remains in custody.
Humberside Police said the three have been bailed pending further inquiries.
All those arrested were detained on suspicion of supplying a controlled drug.
A spokesman also said post-mortem examinations on Mr Wainwright and Mr Smith have been completed but officers are waiting for the results of toxicology tests which could take several weeks.
The spokesman said: "Humberside Police is continuing to encourage anyone who knows somebody who has possession of the drug to either hand it in to a local police station or dispose of the substance as soon as possible and contact Humberside Police."