A male nurse on trial over the deaths of 29 patients in Germany has admitted killing some people in his care.
Mr Letter admits some killings but says he cannot recall other cases
Stephan Letter, 27, told the court in Bavaria that his actions "cannot be justified under any circumstances" but said he had acted out of compassion.
He asked the court to convert the 16 murder counts he faces to manslaughter, which carries a lesser penalty.
He also faces 12 manslaughter counts, one of killing on demand and two of attempted manslaughter.
Mr Letter said the killings were designed to spare people suffering.
The nurse was arrested in July 2004 following a police inquiry into missing medication at the clinic in Sonthofen, where he worked.
Mr Letter told police at the time of his arrest that he had killed 12 patients by lethal injection, but that he could not remember other cases.
On Tuesday, he retracted the statements and refused to say how many deaths he accepted responsibility for.
"I confessed to killings which I did not commit," he told the court.
He did, however, admit that he "took the rest of [the patients'] lives away without being asked, and took away what human dignity they had left".
Investigators found unsealed vials at his home containing enough medicine to kill 10 people, prosecutors told the Bavarian state court in Kempten.
Following Mr Letter's arrest, police exhumed and ordered post-mortem examinations on the bodies of 42 people who had died at the clinic in the 17 months he was employed there.
He was then charged in connection with the deaths of 17 female and 12 male patients aged from 40 to 94.
Most of Mr Letter's alleged victims were more than 75 years old, and their deaths raised no suspicions at the time, the court heard.
Lawyer Wilhelm Seitz, acting for the families of 11 of the dead, said: "He acted relatively indiscriminately and aimlessly.
"Not all of the patients were seriously ill, and he had no contact at all with some of them."