Police arrived at a park shortly before 7am, to notice a woman swinging a body that seemed lifeless. Quickly, they realised that the boy was dead and his mother was pushing him back and forth on the swing.

She has now been taken to hospital, while an autopsy is set to determine the cause of her son’s death.

Diane Richardson, a spokeswoman with the Sheriff’s Office, said: ‘It’s a very sad and tragic situation for the mother, her family, the officers.

‘We’re working very hard on that.’

One witness told deputies she found it strange that the woman had been pushing the child for an unusually long period of time, possibly since the day before, Richardson said.

When the officers arrived they found the 24-year-old woman still pushing the child in the swing, and they realized immediately that the boy was dead, Richardson said.  The child had no signs of obvious trauma, she said, and had been dead for at least several hours.

The office of the chief medical examiner in Baltimore will perform an autopsy on the boy. The mother, who was not identified, was transported to a nearby hospital for medical tests, police said. The investigation is ongoing.