By CBS3 Staff

PHILADELPHIA (CBS) — The body of an Upper Darby pregnant woman, who had been missing since last week, was found in a wooded lot in Southwest Philadelphia late Monday night. Philadelphia police say the body was identified as 21-year-old Dianna Brice, who was last seen last Tuesday and was four-and-a-half months pregnant.

The family’s private investigator tells Eyewitness News police were able to identify Brice from her tattoos.

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Police say she had been shot. This is now a Philadelphia police homicide investigation.

The body was found around 11 p.m. Monday at 58th Street and Eastwick Avenue in Southwest Philadelphia. It is not clear what tip led police to the location of the body in a desolate area.

This discovery comes days after mother Betty Cellini told Eyewitness News that her 21-year-old daughter had not been seen since last Tuesday. She says she and Brice were in Landsdowne at a laundromat when Brice’s boyfriend Justin Smith came to pick her up to go to a pharmacy in Kensington at around 11:30 a.m.

Dianna Brice and Justin Smith

During that trip, she says the two got in an argument, and Brice, who is four-and-a-half months pregnant and has a child at home, got out of the car.

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“He was the last one to see her,” Missing person investigator Kevin Ryan said. “They had a fight.”

Cellini says she threatened to file a police report and that’s when Smith disappeared.

“His background shows that he could harm somebody without going into further detail,” Ryan said. “She had a life-threatening medical condition, not that you’re doing anything different than when it’s a fluid situation, but you don’t want to miss any steps.”

At about 5:30 p.m. that afternoon Smith’s car was found on fire at Florence Avenue and Cobbs Creek Parkway. Neither Brice nor Smith had been seen since then.

Eyewitness News spoke with Upper Darby police on Monday before Brice’s body was found.

“This one has everyone perplexed. Nothing really makes sense here. The two of them just completely since, like I said, Tuesday, March 30, have gone off the radar and haven’t spoken to anyone,” Upper Darby Police Superintendent Timothy Bernhardt said. “Both family members, both Justin Smith and Dianna Brice, have said that that’s not normal for either one not to be in contact with anyone. Dianna also has a 4-year-old child at home that she has not gone a day or minute without speaking to. As well as Justin Smith, family members say this is not like him to just not call or check in with anybody.”

Bernhardt says today’s finding is the result of round-the-clock work between a number of agencies to bring the family closure.

“It’s terrible. Words don’t express how sad it is for a young woman who leaves behind a 4-year-old child and was three to four months pregnant with her second. Words don’t describe how sad it is for her and her family,” Bernhardt said.

Justin Smith remains missing. At this time, he is considered a person of interest.

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CBS3’s Howard Monroe and Alecia Reid contributed to this report.