Filed on June 28, 2018 | Last updated on June 28, 2018 at 08.08 am

A search of the suspect's home unearthed large quantities of cadmium, mercury and lead.

Police in Germany on Wednesday announced they were investigating a man suspected of poisoning the sandwiches of up to 21 co-workers with heavy metals over a period of almost two decades.

The 56-year-old suspect, whose name was not revealed, was an employee at a company located in Schloß Holte-Stukenbrock, near the city of Bielefeld, and has been linked by officials to the premature deaths of nearly two dozen colleagues going back to the year 2000, reports Efe.

He was arrested following CCTV footage that appeared to show him sprinkling an unidentified substance on a co-worker's sandwich or "Pausenbrot" (break-time bread), as the midday snack is known in Germany.

The intended victim detected the strange powder, later found to be lead acetate, and informed authorities, a step which eventually led to the suspect's arrest.

A search of the suspect's home unearthed large quantities of cadmium, mercury and lead. He currently remains in pre-trial custody.

The criminal investigation bureau of the region of North Rhine-Westphalia was now probing the deaths of 21 former employees at the company over the past 18 years, all of which occurred shortly before they were about to go into retirement.

At the time, most of the deaths were attributed to heart failure or cancer, symptoms that would be consistent with heavy-metal poisoning as the accumulation of these toxic elements in the soft tissues of the body can cause a variety of ailments including permanent damage to vital organs.

According to toxicologists, lead poisoning is very difficult to detect without there being a reason for suspicion, since symptoms (headaches, nausea, fatigue, abdominal pain, stained gums and seizures) can be attributed to a variety of illnesses.

A special committee comprising 15 experts was convened by police in order to determine whether the 21 apparently-natural deaths were actually murders.

Following the latest revelations, two of the suspect's co-workers-one of which is currently in a coma while the other is receiving dialysis treatment-are now assumed to have also been poisoned with heavy metals.