Niels Högel was jailed in 2015 for two murders and three attempted murders. He said at the trial that he acted out of “boredom”

A nurse serving a life sentence for a double murder is suspected of being responsible for 102 deaths at two hospitals, a number that would make him Germany’s most prolific postwar serial killer.

Niels Högel, 41, was convicted in 2015 of two murders and three attempted murders by giving intensive-care patients overdoses of powerful drugs.

After his conviction investigators exhumed 134 bodies from 67 cemeteries to test them for drugs that Högel admitted using to induce heart attacks so he could play the hero by trying to resuscitate the patients. He said at his trial that he acted out of “boredom”, feeling euphoric when he brought a patient back to life and devastated when he failed.

Police said that they expected to bring charges against