Officers were initially searching at the Cedar Tree Apartments at 148 Avenue between Burnside and Stark Street when they received the report of a missing child around 2 a.m. Tuesday. Initial reports were that they were looking for a toddler.
Police checked with every relative of the family trying to locate the child or gain information on the child's whereabouts.
At about 7 a.m., a woman unrelated to the family walked outside of her home and discovered the baby boy underneath a tree in her front yard in a tee shirt and a diaper.
"So. Found a baby on my lawn this morning. That's new," the woman wrote on twitter. "The baby is fine. Cold, but safe."
Officer Kevin Macho responded to the radio call that the baby had been found and immediately took custody of the boy at the home on Northeast 139 Avenue, just 11 blocks away from the address where the baby went missing. Paramedics then took the baby via ambulance to the hospital for evaluation. He was okay.
"It obviously felt good. We didn't know the status of the baby earlier, so it's nice to hold a 4-month-old that's safe," Macho said.
Officers said the teen took the baby before abandoning him under a tree and then returned to the home where she was staying with the baby's family.
Detectives interviewed her before taking her to the Donald E. Long Juvenile Detention Home where she has been charged with one count of second-degree kidnapping. Police have not released any further details about a motive for Harper's actions, but they do not believe any others were part of the baby's kidnapping.
The woman who found the baby later tweeted on KPTV's twitter, "Glad the baby's safe, hope he lives a long, productive, drama-free life from now on."