BERLIN (AP) — A judge in Germany has found a man guilty of poisoning his co-workers' sandwiches with mercury and other substances over several years and sentenced him to life in prison.

German news agency dpa reported a regional court judge gave 57-year-old Klaus O. the sentence on Thursday after convicting him of attempted murder.

O. laced colleagues' lunches with chemicals such as mercury and lead acetate between 2015 and 2018. One is in a coma with irreparable brain damage. Two more have serious kidney damage.

He was arrested in May after surveillance video showed him putting a suspicious powder on a colleague's sandwich at a business in western Germany.

Life sentences in Germany usually can be reduced after 15 years. But the judge in Bielefeld ordered O. ineligible for such a reduction, saying he was inclined to commit more crimes.