A German nurse serving a life sentence for two murders may have killed more than 100 patients, prosecutors have said.
Niels Hoegel was jailed for life in February 2015 for killing two intensive care patients at a hospital in Delmenhorst near the northern city of Bremen.
His crimes came to light after he was convicted of attempted murder in another case – with prosecutors reviewing more than 500 patient files and hundreds of hospital records.
Detectives also exhumed 134 bodies from 67 cemeteries and questioned Hoegel six times.
In August, prosecutors said they believed that Hoegel may have killed at least 84 other patients, but 16 more suspicious cases have since come to light.
Hoegel's trial heard how he gave patients overdoses of heart medication and other drugs because he enjoyed the feeling of being able to resuscitate them.
Prosecutors say they expect to bring more charges against him by early 2018.
Any additional convictions could affect Hoegel's possibility of parole, but consecutive sentences are not a part of the German legal system.
He was a nurse at Oldenburg hospital from 1999 to 2002 before going to work in Delmenhorst between 2003 and 2005.