'Niels Högel did not mercy kill': victim's grandson

Germany's most prolific serial killer, Niels Högel, has confessed in court to killing 100 patients while they were in his care.

The grandson of one of his victims, Christian Marbach, tells the BBC's Jenny Hill how he reached out to Högel to find answers.

The former nurse is currently serving a life sentence for six deaths and he is on trial for 100 deaths between 1999 and 2005.