BERLIN (AP) — A German court convicted a male nurse Tuesday of three cases of murder for injecting elderly patients with fatal doses of insulin because he was tired of caring for them or wanted to steal their belongings.

The Munich regional court sentenced the defendant, previously identified as Grzegorz Stanislaw Wolsztajn, to life imprisonment. It ordered him to remain imprisoned beyond the minimum 15-year life term.

The 38-year-old defendant, a Polish citizen, was arrested in 2018.

Prosecutors had accused him of killing six of his patients, but later acknowledged that not all of the deaths could be conclusively attributed to him, the dpa news agency reported.

Wolsztajn, who as a diabetic had access to insulin, himself described the killings as “bestial murders” in court, dpa reported.

Judges also convicted him of attempted murder, robbery resulting in death and serious bodily harm.

The case echoes that of German nurse Niels Hoegel, who was given a life sentence last year for killing 85 patients by deliberately bringing about cardiac arrests.