A healthcare worker in Germany has been jailed for life after being found guilty of killing three patients in his care.
Prosecutors told the court in Munich they suspected the man, named as Grzegorz W, had killed more victims.
Prosecutors accused him of injecting patients with lethal doses of insulin.
He was also found guilty of attempted murder in two cases, as well as dangerous bodily injury and stealing from his victims.
Doctors became suspicious when they discovered a fresh needle mark on an 87-year-old patient who had just died, DW reports.
The nurse had access to insulin because he is diabetic.
The 38-year-old, who is Polish, refused to testify in court, but apologised to the families of his victims.
"What I have done is very brutal and remains brutal," he said in court.
He was initially charged with six murders, but only found guilty of three.
The judge said that patients and family members had raised concerns about the nurse before his arrest.
According to AFP news agency, one of his victims described Grzegorz W as "the devil" to his housekeeper, shortly before his death.
Grzegorz W had spent time in care homes as child and had a record of petty offences as an adult.
He was an unemployed locksmith in Poland and took a crash course in nursing to find work in Germany, BR 24 reports. He then worked as a nurse in 69 locations.
Local media have drawn parallels between this case, and the case of nurse Niels Högel, who was convicted of murdering 85 patients at two hospitals last year. Högel is believed to be the most prolific killer in Germany's modern history.