According to CPS officials, the girl and her two siblings - 5-year-old and 1-year-old boys - were removed as the agency investigated allegations of physical abuse related to her head injury.
The three siblings were brought back in February.
In an exclusive interview with ABC13 Eyewitness News, Brittany Bowens, Davis' mother, said it was determined a fall was the cause of the girl's injuries.
The new details comes in the midst of Texas EquuSearch participating in the search of the girl. An Amber Alert was issued Sunday for the 4-year-old who was possibly taken by three men.
Maleah's stepfather said she was last seen in the 16500 block of the Southwest Freeway on Saturday around 6 p.m.
Maleah was wearing a pink bow in her hair, a light blue zip jacket, blue jeans and gray, white and pink sneakers.
She is described as an African-American female with black hair and brown eyes. She stands 3 feet tall and weighing 30 to 40 pounds.
Volunteers with Texas EquuSearch are staging a search on foot and by ATV in a field in northeast Houston near Highway 59 and Greens Road.
WATCH: 'We believe in miracles'
"We want to start checking every single dumpster just in case," said Texas EquuSearch's Tim Miller. "We believe in miracles. Let's hope we get one."
"I'm choked up right now thinking about her," Miller told ABC13. "I've been on these cases before. If it doesn't touch your heart, and you don't get emotional, you're just not human."
Bowens told ABC13 on Monday that she's terrified for her daughter.
"My spirit is so broken, I feel so lost. I can't concentrate, I can't focus. It's so overwhelming for me. It doesn't seem real," Bowens said tearfully.
RAW VIDEO: 'I'm terrified for Maleah' Mom of missing girl speaks to ABC13
MALEAH DAVIS: What we know about missing Houston 4-year-old who was possibly kidnapped
Maleah's stepfather, Darion Vence, told police that he, his 1-year-old son and Maleah were all abducted by three Hispanic men.
In a press conference Saturday afternoon, police said Vence was on his way to pick up Bowens at Bush airport when he was forced to pull over.
"He hears a popping noise like he has a flat tire," said detective Mark Holbrook.
Vence told police that's when the three men got out and approached him while he was pulled over near Greens Road and Highway 59.
Vence says the men were in a 2010 blue Chevrolet crew cab pickup truck.
2/2: Photo of assault victim, Mr. Darion Vence, who is Maleah's stepfather, stated he was unconscious for almost 24 hrs. Detectives ask anyone who saw Darion or Maleah after 9 pm Friday (May 3) to 6 pm on Sat to contact HPD Homicide 713-308-3600 or @CrimeStopHOU at 713-222-TIPS. pic.twitter.com/nuZHA1EQPY— Houston Police (@houstonpolice) May 5, 2019
"One of them makes a comment saying that Maleah looks very nice, looks very sweet," said Holbrook.
Police said that's when he was hit on the head by one of the men and lost consciousness.
Vence says the abductors kept Maleah with them and drove off.
"He really doesn't know where he is until 6 p.m. on Saturday," said Holbrook.
Vence said he woke up on the side of Highway 6 near First Colony Mall. His son was with him, but Maleah was not.
Police said Vence went to Houston Methodist Hospital in Sugar Land around 11 p.m. to seek treatment for his injuries with his son.
Meanwhile, police say Bowens was waiting for Vence at the airport and did not report the family missing to police.
They say she ultimately got another family member to pick her up.
Bowens tells ABC13 they called police Saturday morning to file a report because they were concerned after not hearing from Vence.
"We're hoping the public can give us any information about anybody who has seen Darion during that period of time because he doesn't really know where he was or what's going on there," said Holbrook.
Investigators have spoken with Maleah's biological father and he is cooperating with police.
Holbrook said they are also concerned because Maleah has had several brain surgeries and requires a lot of care.
Anyone with information on Maleah Davis' whereabouts is urged to contact HPD at 713-308-3600 or Crime Stoppers at 713-222-TIPS.