Matt Morgan, an attorney for Parker's family, disclosed the discovery to WFTV, ABC News' affiliate in Orlando.
According to Parker's sister Lauren Erickson, Orlando police asked members of their family to come in to view a photo of an iPhone 4. The family was instantly able to identify the phone as Parker's.
"They literally just found a needle in a haystack," Erickson told WFTV. "My heart dropped, it went up, it went all around. It is her phone. It is her phone case. It is the one."
Police have centered their search for Parker on the missing cell phone. Her final phone calls are considered major clues as to the reason for her disappearance, including a nine-second message for her father on the day before she vanished, asking him to call her.
Parker, 33, has been missing since Nov. 17, the day she and her fiance, Dale Smith, 40, were seen on "The People's Court" airing their dispute over a $5,000 engagement ring.
The search for Parker has gone on for 20 days and has spanned two counties. Aside from her vehicle, a black Hummer, her phone is the only piece of evidence that has been discovered.
"[This] gives me great hope that we are getting closer, getting closer to her or finding who knows where she is," Erickson said.