A mother has been arrested on suspicion of murdering her three-month-old son who she previously claimed had been snatched from his pram.

32-year-old Dijana L. reported her baby had been kidnapped on June 18, however cops could not find evidence to support the claim. 

The child was found dead the following day in a river just 500 metres from her home in Renningen, Germany.

Now, Dijana L. has been arrested on suspicion of murder. She had previously been accused of abandoning her child and faking the kidnapping.

Dijana L. reportedly only found out she was pregnant in her fifth month, and her son Adrian was born prematurely.

They lived in a cramped, run-down flat, where neighbours said they frequently heard Dijana arguing with her ex-boyfriend.

'It was always loud there, chaotic,' one neighbour recalled.

A new boyfriend would occasionally stay at the property, but was not a permanent presence. 

Her ex-boyfriend's mother also lived there, and former colleagues said Dijana was desperate to leave.

Speaking to Bild, colleagues said: 'Dijana tried to find a better apartment for herself and her new boyfriend. She wanted to escape the cramped conditions and end the chaos.'

Emergency responders discovered Adrian's body lying in or near the Rankbach stream on Friday at around 1.45pm.

Police identified the body as the three-month-old child who had been reported missing the day before.

Dijana had taken her child to the Rewe supermarket, around 800 metres away from her home.

Speaking to Bild, her mother said: 'My daughter came home from shopping, she had bags with her and wanted to carry them up to the second floor.'

Dijana then left the boy in his stroller on the pavement in front of the house, but claimed he was gone when she returned.

She initially told authorities that a stranger snatched the child while she was inside.

A massive manhunt was launched immediately after the missing persons report was filed, with drones, helicopters, firefighters and 40 rescue dogs deployed.

Police began at the scene of the crime and worked outwards, and the search was called off after the discovery of the deceased baby on June 19.

Cops are now investigating Dijana. Police have set up a homicide unit to aid their investigation.

A 3D model has also been used to assist officers, according to local media.

Reacting to the infant's death, the mayor of Renningen, Melanie Hettmer, previously said: 'I am speechless and deeply worried.'

This is a breaking news story. More to follow.