But on Saturday morning, a judge ordered the agency to release Aryana immediately into her mother's custody, and she was reunited with Cassieri at a family friend's home in the afternoon.
At first, "she looked like she wasn't sure if she was going to stay with me," Cassieri said. "I was like, 'You're going to stay.' Then she was just happy."
Aryana, who lives with her mother in Broward County, had been visiting her father, Armone Stanley. The two were preparing to leave for Philadelphia International Airport on Wednesday when Stanley, carrying his daughter's bags to his car, was ambushed and shot 19 times, police said.
Aryana found his body, riddled with bullet holes, and tried to wake him. When he didn't stir, she hid in the apartment alone.
In Florida, a frantic Cassieri asked a landlord to check on Stanley's apartment, and on Thursday he discovered the body on the second-floor landing; Aryana was curled in her father's bed.
Cassieri arrived in Philadelphia hoping to take her daughter home immediately - "as soon as they tell me I can go, I have to go," she said. Instead, DHS officials permitted her to see Aryana for just 10 minutes on Thursday and two hours on Friday.
On Friday night, Cassieri said, Aryana kicked and screamed as her mother left the room.
"She was asking why I couldn't take her with me," Cassieri said. "You can't explain, 'I want to take you, but I can't.' "
DHS officials said in a statement Saturday they "fully support" the judge's decision to return Aryana to her mother, and kept her in temporary care because of an initial lack of information on her case.
"DHS has to take all the facts into consideration in assessing the safety of children in our care," the statement read.
DHS officials will visit Cassieri and Aryana on Sunday, and the two must still attend a custody hearing on Monday, but as there are no allegations of abuse or neglect against Cassieri, it's likely they will be able to return home.
In the meantime, the family is simply trying to keep Aryana's mind off the last week.
"Right now, we're just trying to keep her occupied. She's just drawing and coloring and stuff. She's being a regular kid," Cassieri said.
Cassieri, for her part, is still struggling with the emotional overload she's dealt with this week.
"I've gone from being overwhelmed with grief to being scared to being mad," she said. "I'm never coming back here. I cannot believe that they put me through that much."