A German nurse has been jailed for life after being convicted of murdering 85 patients.

Niels Hoegel had been charged with 100 counts of murder over allegations he killed patients at two hospitals in northwestern Germany between 1999 and 2005.

The conviction makes him Germany’s most prolific serial killer in the country’s post-war history.

The court in Oldenburg heard he had killed his victims by putting them into cardiac arrest because he enjoyed the feeling of being able to resuscitate them.

Prosecutors asked the court to recognise the “particular seriousness of the crimes” to ensure the 42-year-old served more than the standard 15 years in jail.

Inside Germany’s abandoned ‘forbidden city’ Show all 8 1 /8 Inside Germany’s abandoned ‘forbidden city’ Inside Germany’s abandoned ‘forbidden city’ A Lenin monument stands in front of the abandoned "Haus der Offiziere" the headquarters for the Soviets' military high command in former East Germany, at the Wuensdorf neighborhood of Zossen. AP Inside Germany’s abandoned ‘forbidden city’ Photo guide Werner Borchert pose for a portrait in the main entrance of the abandoned "Haus der Offiziere", the headquarters for the Soviets' military high command in former East Germany at the Wuensdorf neighborhood of Zossen. AP Inside Germany’s abandoned ‘forbidden city’ A monument of the Soviets' stands in front of a abandoned house at the compound of the headquarters for the Soviets' military high command in former East Germany at the Wuensdorf neighborhood of Zossen Markus Schreiber AP Inside Germany’s abandoned ‘forbidden city’ The doors stand open in a corridor of the abandoned "Haus der Offiziere", the headquarters for the Soviets' military high command in Zossen, eastern Germany AP Inside Germany’s abandoned ‘forbidden city’ The staircase inside the abandoned "Haus der Offiziere", the headquarters for the Soviets' military high command in former East Germany, at the Wuensdorf neighborhood of Zossen. AP Inside Germany’s abandoned ‘forbidden city’ A Lenin monument stands in front of the abandoned "Haus der Offiziere", the headquarters for the Soviets' military high command in former East Germany, at the Wuensdorf neighborhood of Zossen. AP Inside Germany’s abandoned ‘forbidden city’ A part of the abandoned "Haus der Offiziere", the headquarters for the Soviets' military high command in former East Germany at the Wuensdorf neighborhood of Zossen. AP Inside Germany’s abandoned ‘forbidden city’ Views out of a window in the abandoned "Haus der Offiziere", the headquarters for the Soviets' military high command in former East Germany at the Wuensdorf neighborhood of Zossen AP

Hoegel worked at a hospital in Oldenburg between 1999 and 2002 and another hospital in nearby Delmenhorst from 2003 to 2005.

He is accused of killing patients aged between 34 and 96 beginning in 2000 and only stopping in 2005 when he was caught injecting a patient with ajmaline.

But he has also previously told investigators he had killed patients in Oldenburg too.

As a result, authorities have investigated hundreds of deaths, exhuming the bodies of former patients.

During the seven-month trial, Hoegel admitted to 43 of the killings, disputed five, and said he could not remember the other 52.

He expressed regret in a closing statement on Wednesday, saying he realised how much pain and suffering he had caused with his “terrible deeds”.

“To each and every one of you I sincerely apologise for all that I have done over the course of years,” he said.

German nurse Niels Hoegel who killed 'out of boredom' could be country's worst serial killer after being charged with 97 murders

Hoegel has already spent a decade in prison for other murders, and was convicted in 2015 of two murders and two attempted murders.

There are no consecutive sentences in the German system, but the court's ruling on the seriousness of his crimes means he is highly likely to remain incarcerated after the standard 15-year term is up.