A nurse serving a life sentence for two murders is going on trial on charges that he killed a further 100 patients at two hospitals in Germany.
Niels Hoegel's trial is to open on Tuesday in the northwestern city of Oldenburg.
The murder charges against him stem from his time at a hospital in Oldenburg between 1999 and 2002 and at another hospital in nearby Delmenhorst from 2003 to 2005.
Hoegel was convicted in 2015 of two murders and two attempted murders.
During that trial, he said he intentionally brought about cardiac crises in some 90 patients in Delmenhorst because he enjoyed the feeling of being able to resuscitate them.
He later told investigators that he also killed patients in Oldenburg.
Authorities subsequently investigated hundreds of deaths.
