JACKSONVILLE, Fla. – The parents charged with the murder of a 4-year-old beat the girl to death on Friday using a 1-by-2 piece of lumber, and the abuse of the child had gone on for months, according to the Jacksonville Sheriff's Office.

John Ross Norfleet, 31, and Shavonn Norfleet, 33, were booked into jail Saturday afternoon, charged with aggravated child abuse and aggravated battery on a child using a deadly weapon.

The Jacksonville Sheriff's Office said that once the medical examiner's report showed the child, named Jada, died of multiple blunt-force traumas, the charges were upgraded to second-degree murder.

At a news conference Tuesday, police said Jada's father and stepmother hit her with the board as a form of discipline.

"I'm not trying to minimize it by saying discipline. They beat the child," JSO Assistant Chief Chris Butler said.

Police said that when paramedics responded to a medical call at the Fountains at Deerwood apartment complex on Southside Boulevard late Friday night, they recognized possible signs of abuse on the 4-year-old and called police.

Jada was taken to Wolfson Children's Hospital, where she died.

What Jada did leading up to the beating that killed her is still under investigation, JSO said.

Butler said investigators are constantly faced with tough situations and never know what to expect when they get out to a scene.

"These homicide teams, they go out there day in and day out. Especially when it deals with children, it's very horrific and horrible," Butler said. "But it's a matter of being a professional and moving through the leads in the case and following up and bringing closure to other family and getting the other children in the family some assistance."

Shavonn Norfleet's father, Daren Rupert, lives in Michigan and said in his heart he believes there must be some sort of misunderstanding because he said Shavonn is a very loving person. But he said if she did wrong by Jada, then she needs to face the consequences.

"It's hard to process right now. It's something that no one would ever imagine. Never would've thought anything of this nature," Rupert said. "Shavonn was a very loving child, especially with kids, all her nieces and nephews, they love her."

Rupert said his daughter, who lived in Michigan a few years ago, and John Norfleet kept in touch online before tying the knot.

"They met through a mutual friend. She went to Jacksonville and called me and told me she was about to marry John," Rupert said. "I know nothing about him other than he's a school teacher."

Rupert said the two have a child together, Summer, the youngest of the three. The two older children were John Norfleet's from a previous marriage. Rupert said he never met Jada but said no matter what, no child deserves to be beaten to death. 

"If what JSO is saying happened, we are very disappointed," Rupert said. "Very sad. We're sad that a 4-year-old is no longer here, period. But for her to have participated in something like that makes it even worse."

Rupert said he hopes to get the full story from his daughter soon, and he wants the other two children to end up with family members and not in the care of the state organization.

Father a high school math teacher

For the past two years John Norfleet has taught math at Andrew Jackson High School. 

The school's website includes a biography of Norfleet, which mentions his wife, Shavonn, and three daughters. 

"The district's process regarding employees who have been arrested and charged with a crime -- particularly an alleged crime where staff have direct contact with students -- is to remove them from the work environment pending the completion of an internal investigation," the district said in a statement. "The individual would be assigned to other duties outside the school and away from all student contact."

Duval County school officials released his personnel file. He was hired from Detroit, where he taught math for four years. Norfleet's first teacher evaluation in the county rated him effective, enabling him to get a pay raise.

One woman who was listed as a reference on Norfleet's resume called him one of the nicest men she'd ever met.

Department of Children and Families officials told News4Jax that they had no prior involvement with the Norfleets.

"The (couple's) two surviving children are in protective custody," DCF spokesman John Harrell said. "They've been through a very tough ordeal. They've lost their sister. What we need to do is help them in any way we can, counseling, therapy, any services we can provide to help these children."

Harrell added that DCF will fully investigate the case, as it does with all deaths of children. He also asked anyone who suspects a child is being abused or neglected to call the DCF's abuse hotline at 800-96-ABUSE or 800-962-2873.

Both John Norfleet and Shavonn Norfleet are due back in court Feb. 23.