Though her body hasn't been found, police say the tragic end for a Bronx woman who went missing weeks ago has been revealed, and her boyfriend is behind bars. NY1's Jose Martinez has the details.

Juana Alvarez hadn't been seen around her Grand Concourse apartment building since July — and two weeks ago, a missing persons report was filed for the 52-year-old mother.

On Tuesday, authorities revealed why.

44-year-old Miguel Bonilla was charged with fatally stabbing her inside this second-floor apartment.

"They seemed like they had a good relationship, there seemed like nothing out of the ordinary," said one neighbor who spoke to NY1. "What's strange to me is that if you was her boyfriend, you was so concerned about her, why you didn't look for her? Where were you? What you was doing?"

Bronx prosecutors said Bonilla admitted on video that he killed Alvarez.

They said he stabbed her in the head and chest with a knife he had hidden beneath a pillow.

This after police at the 44th Precinct said they were tipped off by one of his friends on Monday morning that he had confessed to the killing during a phone call.

Authorities said they also have surveillance video of Bonilla taking a shopping cart out of the apartment building with what they believe is the victim's towel-covered body inside.

"I thought it was really crazy that this happened right next door," said another neighbor.

Neighbors described Bonilla as a quiet man who had been making himself scarce around the building in the weeks since Alvarez was last seen.

"I don't know what happen," said Sandra Ceaprain, a friend of the victim. "He don't look like a bad guy."

Police sources painted a different picture of Bonilla, saying he was arrested 15 times from 1986 through 2012, on charges that included drug possession, attempted robbery and criminal trespassing.

Cops say he was arrested in connection with this incident after jumping a subway turnstile at Penn Station.

"She was a nice person, didn't deserve to die like that," said another neighbor. "He should have never did that to her."

In addition to the second-degree murder charge, Bonilla is also accused of manslaughter and weapons possession.