A young boy killed this week in what police said is a case of child abuse was no stranger to violence, court records show.

This week's incident was the second time 20-month-old Marcus Markee Davis Jr. had been hospitalized, a relative said.

The boy's mother, 22-year-old Shannon Merriman, called 911 on Sunday, saying her son had slipped and hit his head at her apartment on High Meadow Lane in southwest Charlotte. Charlotte-Mecklenburg police charged Merriman on Wednesday with felony child abuse inflicting serious injury.

The child died at Carolinas Medical Center on Thursday as a result of his injuries. Police then charged his mother with murder.

A relative of Merriman's who asked not to be named said Marcus Jr. was a sweet child whose "life was on edge" during his short existence.

"He was a bright child who brought a smile to everyone's face, even as a newborn," she said.

"No child deserves this kind of treatment."

Father jailed in early abuse

Last September, the boy's father and namesake, Marcus Markee Davis, 26, was arrested on charges of felony child abuse inflicting serious injury.

Davis was accused of assaulting his son, causing bleeding in the boy's brain, according to court documents. Marcus Jr. was 7 months old when he was hospitalized last year.

Davis pleaded guilty earlier this year and was sentenced to seven months in jail and three years of probation.

He was also ordered to enroll in and complete a parenting class. He had previously been convicted of simple assault and assault on a female, according to the N.C. Department of Correction.

DSS role is questioned

It's unclear whether the Department of Social Services investigated abuse against Marcus Jr.

A DSS official said the agency was preparing a statement, but it had not been released by Friday evening.

Police would not comment further on the case on Friday.

On Merriman's Facebook page, there are photos of a smiling Marcus, who she described as her "baby boy" and "my life."

The relative who spoke to the Observer said she believes Social Services failed Marcus Jr.

"Little Marcus should (have) never been put back in the hands of his mother or father," she said. Staff researcher Maria David contributed.