Nationwide media attention and a statewide Amber alert ensued after reports of the disappearance of Madyson "Maddy" Middleton in Santa Cruz on Sunday just after 5 p.m. But after police canvassed the affordable housing and arts complex where she lived with her mother — the Tannery Arts Center — they ultimately made a gruesome discovery just before 8 p.m. Monday. The body of a young female believed to be Middleton was discovered in a dumpster at the complex, as the Santa Cruz Sentinel and others are reporting.

Subsequently, and perhaps via tips from residents, a 15-year-old boy who also lives in the complex was arrested on suspicion of murder.

Santa Cruz police are still not clear on whether the teenager knew Middleton, or how well, but they confirmed that he also lived at the complex. His mother can be seen distraught in TV news footage shortly after his arrest and was "screaming hysterically" according to ABC 7.

The discovery of the body was made around 7:55 p.m. Monday, and as CBS 5 reports, Santa Cruz Police Chief Kevin Vogel says they have not positively identified the body and can't describe the clothing on the body because of "the way the body is situated in the dumpster." They do however believe that the body is Madyson Middleton.

The press conference occurred just before 10 p.m. Monday, and the crime scene continues to be processed.

As many local residents joined the search and media attention heightened Monday, suspicion started to be focused on the nearby creek and Paradise Park, and the "heroin highway" among some illegal encampments along the San Lorenzo River behind the complex.

Maddy's mother, Laura Jordan, told ABC 7, "She was riding her brand new scooter, it was a white Razor. She had a black helmet on, she was wearing a purple dress, and she just as happy as can be riding around." Maddy was last seen on a surveillance camera just after 5 p.m. Sunday near the mailboxes pictured above.

Jordan had said, "She's never gone into the woods, and she knows she's not supposed to go down to the creek by herself. People asked if she hides, and she doesn't do that."

Below, footage of the press conference Monday night by Police Chief Vogel.

Previously: Frantic Search After 8-Year-Old Girl Disappears From Arts Center