A German, a former nurse who was convicted in 2015 of murdering two patients, may have killed at least a hundred more, BBC reported.

Niels Hoegel was sentenced to life for injecting fatal doses of heart medication to the two patients and then attempted to revive them so that he could be hailed as a hero, Reuters reported.

In August, after Hoegel failed to remember all the details of his actions, the police exhumed the remains of 134 people who were under his care. Now, police officials say that the former nurse may have killed 38 people at a clinic in the northern German city of Oldenburg and 62 at the nearby town of Delmenhorst.

The toll could rise, Reuters reported, as the police were trying to exhume the remains of some of his possible victims in Turkey.

If found guilty of all the deaths, Hoegel will become one of Germany’s worst serial killers post Second World War, BBC reported.