The mistake was uncovered almost two weeks later, when Jackson was spotted at a shopping mall by a person associated with the social-service agency that saw to her needs, her family said. On Aug. 15, she was admitted to Pennsylvania Hospital's psychiatric ward, officials said.
And finally, on Aug. 19, the Philadelphia Medical Examiner's Office contacted Jackson's family, the woman's mother, Carrie Mae Minnie, said.
The happy news was also a shock.
"I was OK. I was settling down and beginning to accept the idea that she was dead," Minnie said.
"It's mind-boggling, really."
How the whole thing came about begins 15 to 20 years earlier, when Jackson became addicted to drugs and slowly grew apart from her family, who largely live in Trenton. Jackson eventually crossed the river and stayed in Philadelphia, sometimes living on the street.
Then, on July 19, paramedics found an unidentified woman who fit Jackson's description in West Philadelphia, at 59th Street and Locust Avenue, and took her to Mercy Fitzgerald Hospital. The woman died the next day before she could tell anyone her name, and her body was taken to the coroner's office for identification.
By then, Jackson, who had just rented an apartment in West Philadelphia, had been reported missing by Horizon House, the social-service agency charged with her care.
Before long, the coroner concluded that the 5-foot-9, 300-pound body it had was Jackson's and contacted Horizon and her family.
After receiving an e-mail with a color photograph of the deceased woman's face, a Horizon social worker said it was Jackson, according to coroner's spokesman Jim Garrow.
Horizon House declined to comment.
Meanwhile, the Medical Examiner's Office had difficulty contacting Jackson's family. Finally, on July 29, her son Travis was handed the same photograph Horizon had received. The 30-year-old Trenton man also confirmed the image was that of his mother.
"Our policy is that a visual identification by a family member is the gold standard," Garrow said. "We deem that enough to release the body."
The son may not have seen the body proper, Garrow said, because the corpse could have been affected by lengthy storage in the freezer before his arrival.
Travis declined to comment Friday evening.
But the family had their answer: Jackson was dead.
News of her death appeared in the Trentonian and the Times of Trenton. A funeral was planned and held.
Minnie, who remembers last talking to her daughter July 1, accepted the woman's death as the by-product of her drug abuse and unmoored life, although recently she had begun to settle down.
When Jackson was using drugs, she would call at most twice a year, Minnie said.
But after she started getting her life together, her daughter would call every day.
On July 1, Jackson called her mother to say she could no longer afford her phone plan.
So when Minnie had not heard from her daughter in weeks, she was not alarmed.
When the call came saying her daughter was alive and under psychiatric care at Pennsylvania Hospital, the family was again overwhelmed.
"I'm happy that she's alive, but you have no idea what we've been through," Minnie said. "It's an emotional up-and-down."
Philadelphia and Mercer County officials are now working together to exhume the body and figure out who the corpse is.
And officials in Philadelphia are trying to make amends.
Lt. John Walker of Southwest Detectives said he had apologized to the Jackson family, who were very thankful. The Medical Examiner's Office is reimbursing the family for the funeral.
Walker said more stringent identification procedures could have prevented the drama.
"There were some other checks that we could have made here to prevent this from occurring," such as checking the found woman's fingerprints against the ones they had on file for Jackson, Walker said.
The Medical Examiner's Office, on the other hand, denied any wrongdoing. A family member identified Jackson, and that was sufficient.
"This is probably just a worst-case scenario," said Garrow, the Health Department spokesman. "From our perspective, we followed all our policies and protocols. This is how we do it every day."
Though many bodies are identified in person by family members, Garrow said, it is often cheaper and easier to present a photograph to them rather than have them go to the morgue.
Garrow and Walker said this was the first time they had heard of such a misidentification.
For Minnie, the matter is still not settled.
"We're concerned about the other person," she said, referring to the woman they buried. "I wouldn't want that to happen to my daughter."
Contact Theodore Schleifer at 215-854-5607, email@example.com, or follow on Twitter @teddyschleifer.