Walden, of Windsor Mill, was taken into custody about 3 a.m. Thursday after Rocket Tiers notified police of the surveillance camera footage Wednesday evening.
Police said Walden has been charged with first- and second-degree murder, first- and second-degree assault, second-degree child abuse and reckless endangerment.
It was unknown whether Walden had an attorney, but she was expected to appear in court for a bail review Friday morning. Attempts to reach Walden's family or associates at her Windsor Mill apartment were unsuccessful.
The death prompted Rocket Tiers, at High and Baltimore streets east of downtown in the Jonestown neighborhood, to be shut down and placed under emergency suspension.
Reese's family released a statement Thursday, saying they were suffering "tremendous pain" and asking for privacy.
"Our hearts are broken. No family should ever have to experience the loss of a child under any circumstances," the statement said. "We await further information from the unfolding investigation."
Attempts to reach the facility's director, Terri A. Dawson, were unsuccessful Thursday. Brandford said the center had been "very cooperative with us" and police had no reason to believe there was "anything going on besides this particular incident."
Police asked any parents with concerns or suspicions of abuse to call the department's child abuse unit at 443-984-7378.
Parents who send their children to the facility, who are mostly from the Fells Point and Canton areas, expressed shock.
"I've never had any issues with them," Courtney Williams, 34, said of the center staff. "But I can't send my son back there."
The center is permitted to hold 60 children, as young as 6 months old. Its website, which was taken offline Thursday afternoon, said the center had been open for 13 years.
Jonathan Gowen, 32, has sent his son to Rocket Tiers for two years and his family was planning to send their newborn there in the coming months.
"My son loves the teachers. They are great to the kids," he said.
When Gowen picked up his son Tuesday afternoon, he said, the facility was "crawling with detectives and cops," but on the second floor "everything was business as usual: teachers smiling, kids were happy."
Gowen said he wasn't sure what his family would do next. "In general, it's hard to find care in the city, or at least good care," he said.
The Maryland State Department of Education, which includes the Division of Early Childhood Development that oversees day care centers across the state, said the center cannot reopen until it undergoes an inspection.
An emergency suspension has been issued for Rocket Tiers, but hasn't been served because staff had been unable to reach the center director as of Thursday afternoon, Education Department spokesman Bill Reinhard said.
"This is a serious matter. We have a lot of facilities. It's not common [to shut them down,]" Reinhard said.
The owners can file an appeal and go before an administrative law judge, who will decide if they can reopen the center.
In July, an inspection cited the center for six violations, including presenting a health or safety hazard, exceeding the maximum approved child capacity, and not completing all training requirements. All were corrected, Reinhard said.
Reinhard said day care employees must undergo a criminal background check and undergo basic health and safety training. He did not have information on whether Walden passed a background check and received certification, saying it would take some time to pull those records.
Walden's bio, which was still listed on Rocket Tiers' website Thursday morning, noted she had been working at the facility for 21/2 years.
"I have one year of professional childcare experience and six years of part-time babysitting," the bio reads. "I love seeing the children develop new skills like sitting up, crawling and walking. The best part of being an infant teacher is caring for babies who love me as much as I love them. This has been the most rewarding experience for me!"
Williams, who has sent her son to Rocket Tiers for about two years starting when he was 18 months, said Walden was "always so sweet."
She said she was alarmed to see the police presence Tuesday, and said no information was initially provided to parents. The facility sent out an automated message saying the day care was closed, with no additional details.
On Wednesday afternoon, Rocket Tiers sent an email to parents saying a baby had died.
"At this time, it does not appear that there has been any wrongdoing at this point on RTLC," the email said. "We send our deepest thoughts and condolences to the family and the RTLC community."
Rocket Tiers said it was closing to "ensure that our teachers and staff receive grief counseling and that the [police] investigation isn't disrupted in any way." It said it would "resume business when the time is appropriate."
Baltimore Sun reporters Jessica Anderson and Carrie Wells contributed to this article.