— As investigators continued their search for a missing 2-year-old Raleigh boy, police on Friday released the 911 recording that prompted authorities to issue an Amber Alert in the case.

"I woke up – I don't know, I guess maybe 15 minutes ago. The front door was open. There was a package outside, and the 3-year-old was not in the house," an unidentified woman said a 911 call made at 1:11 p.m. Wednesday.

Less than 24 hours later, the search for Tristan Matthew Blue – two months shy of his third birthday – had turned into a death investigation with police charging his father, Steven Daniel Blue, 31, of 5416 Portree Place, Apt. 1, with murder and mother, Briana Loriel Dangerfield, 25, with misdemeanor child abuse.

Police said family members reported that the boy wandered away from Arbor Creek Apartments off Buck Jones Road in southwest Raleigh as early as 7:45 a.m. Wednesday.

Other than an arrest warrant alleging that Dangerfield left her son home unattended while she went to work, authorities haven't provided any details about their investigation.

Also unclear is who made the 911 call.

The caller, whose name was redacted, told a dispatcher she works overnight and that, after waking up and discovering Tristan gone, she walked around the apartment complex calling for him.

"Has he ever walked off before?" the 911 dispatcher asks.

"Sort of. At the old apartment, he was able to open the door. But at this one, he can close it and unlock it, but I haven't seen him be able to open it," the caller said.

Neighbors said the family had lived at Arbor Creek for about eight months.

"They looked like your average family. They were happy. The little boy was happy," one resident, who did not want to be identified, said Friday.

Another on Thursday said that she went to do laundry around 10:15 a.m. Wednesday and saw the door to the family's apartment cracked open and papers scattered on the floor.

A couple hours later, the neighbor said, she noticed that the door was still open. She said she was about to contact the apartment complex's office when officers knocked on her door, asking if she had seen Tristan.

Police searched until nightfall Wednesday, and sometime overnight into Thursday, they said, "investigative developments" led detectives "in a new direction" in the case.

As a memorial grew Friday on the sidewalk of Arbor Creek, Steven Blue and Dangerfield made their initial court appearances.

He remains in the Wake County jail without bond. Dangerfield was being held on a $100,000 bond.