Lovily K. Johnson
Lovily Johnson's lawyer says she is mentally unwell Facebook / Lovily Johnson

A young mother accused of murdering her baby and walking into a children's hospital with his decaying corpse has been deemed fit to stand trial.

Lovily Johnson, 22, has been charged with first-degree murder and first-degree child abuse following the death of her son Noah Edward Johnson in July 2017.

She allegedly strapped the six-month-old to a car seat in their Wyoming apartment without giving him food or water for several days during midsummer heat wave temperatures of 30C.

She walked into DeVos Children's Hospital Michigan carrying Noah's lifeless body – which was already decomposing – on 19 July.

Johnson told detectives she smoked cannabis with friends and left Noah alone for up to 12 hours on the days before his death.

"[She] admitted that Noah was under her care and no one else's care for the last four days. Johnson admitted to being at home multiple times a day during that time frame,'' Detective Robert Meredith wrote in an affidavit.

Defense attorney Jonathan Schildgen has sought two competency tests for his client, who he believes is severely mentally ill. However, both have returned the verdict that she is fit to stand trial.

When Johnson first appeared in court in last year she did not appear to understand the charges being read out by the judge. He had to clarify, saying: "Well, let me make it really clear. They alleged you killed a young child and that you physically abused it. Does that make sense to you?''

"Yes sir,'' Johnson replied.

Lovily K. Johnson
Lovily Johnson and Noah, deceased Facebook / Lovily Johnson

Johnson's Facebook page suggests that Noah was born in January 2017. Messages from family members at the time complain that they had not been informed about the pregnancy.

On 10 June, Johnson made an apparent reference to Noah's father absconding from his paternal responsibilities, when she wrote: "How U A Man & [don't care] About Yo Own Seed! Sound Like A Weak Bi*ch To Me!"

The Detroit Free Press reported that she was the victim of domestic violence in 2016 carried out by the father of her daughter. It is unclear if this is also Noah's father.

Johnson is currently held without bail while her other child – a two-year-old girl – is in the care of the state. If convicted of both felonies, the mother will face mandatory life imprisonment. She next appears in court on 15 February.