A 24-year-old mother in the US state of Maryland has been hospitalized for medical evaluation after police found her pushing her dead 3-year-old son on a swing.

“We think she was there as of yesterday,” a Sheriff’s Office spokesperson said on Friday. “We don’t know if she ever left during the night. It doesn’t appear that she did.”

According to The Washington Post, police responded to Wills Memorial Park in La Plata, Maryland, at around 7:00 a.m. on Thursday after someone called police and said that a woman had been pushing a child on a swing for “an unusually long period of time.”

Official said the woman and her son might have been at the park since the day before the incident.

Police arrived and found the woman pushing the toddler on a swing at the playground and noticed that the three-year-old had been dead for at least several hours.

“We have a lot of work to do to try to figure out what happened to this child,” said Diane Richardson, a Sheriff’s Office spokeswoman.

The cause of the child’s death is not yet known. The Charles County Sheriff’s Office said that the body of the kid did not show signs of trauma, and Office of the Medical Examiner in Baltimore will perform an autopsy to find out the cause of death.

GJH/GJH