'Serial killer doctor murdered four patients in their homes before setting fire to their properties to cover his tracks'

A German doctor allegedly murdered four patients in their homes before setting fire to their properties to cover his tracks.

The 39-year-old, who reportedly worked in the palliative care team of a nursing service in Berlin, was arrested on Tuesday on manslaughter and arson charges, according to a joint statement by police and the local prosecutor's office.

The doctor allegedly killed four elderly women being cared for by the nursing service between June 11 and July 24, but police has yet to determine how exactly these patients aged 72-94 died.

To cover his tracks, the man set fire to the women's homes and in one case, even called one of the victims' relatives and lied about the woman being unresponsive to conceal the killing when the fire in her apartment went out by itself, police say.

The man started his alleged killing spree on June 11, when he is said to have killed a 87-year-old woman in her home in the Neukoelln district of Berlin before setting her apartment alight.

The fourth victim, 72, was killed and her home in an apartment building set on fire in the Plaenterwald district adjacent to Neukoelln around noon on July 24 (scene pictured above)

Emergency services called to put out the fire around 12.30pm initially managed to resuscitate the woman, but she later died in hospital. 

Three other residents in the block of flats suffered minor injuries in the fire. 

The second alleged case of manslaughter happened nearly a month later on July 8 just a few miles away. 

Prosecutors believe that the doctor killed a woman aged 76, also living in Neukoelln, and tried setting a fire, which went out by itself. 

He then attempted to cover up the killing by calling a relative of the victim. He told them that he was standing in front of her apartment and that no one was responding to him ringing the doorbell.

On July 15, just one week later, police believe the alleged serial killer struck again when a 94-year-old woman died in her flat with her kitchen being lit on fire in the same Berlin district as the woman a week prior.

The fourth victim, 72, was killed and her home in an apartment building set on fire in the Plaenterwald district adjacent to Neukoelln around noon on July 24. 

A neighbour noticed the fire in the woman's ground floor flat and alerted the local fire service at 1.15pm, who found her dead.

Berlin's public prosecutor's office has charged the alleged serial killer with four cases of manslaughter, three cases of attempted particularly serious arson and one case of completed arson. The investigation is ongoing.