The public prosecution department is looking into a further 12 people suspected of selling suicide powder “substance X” to members of the public, a spokesman has told broadcaster NOS.

Five of the 12 have links to the pro-right-to-die lobby group Coöperatie Laatste Wil (CLW), which could leave them open to charges of membership of a criminal organisation, the broadcaster said.

On Tuesday, judges in Den Bosch jailed 29-year-old Alex S for 3.5 years, 18 months suspended, for supplying the chemicals to 10 people who went on to end their lives. It is illegal in the Netherlands to help someone commit suicide.

CLW has said in a reaction to the jail term handed down to Alex S that it is convinced he acted with good intentions. “CLW strives for an end to the criminalisation of helping someone to kill themselves,” the organisation said.

“The law on euthanasia means that doctors are not prosecuted if they meet certain conditions but we want to expand this to cover end-of-life counsellors and the relatives of those who feel their life is complete.”

Anyone struggling with suicidal thoughts can talk or chat anonymously with the helpline 113.nl or call the free number 0800-0113.