Philadelphia’s investigation into the treatment of MOVE victims’ remains will focus not only on the box discovered at the Medical Examiner’s Office last week, but also on a review of the city’s handling of all remains from the infamous 1985 bombing — including those transferred between two Ivy League universities, Mayor Jim Kenney said Tuesday.

The investigation will go “as wide and as deep as we can” and will also scrutinize policies and procedures in the Medical Examiner’s Office, Kenney said during a meeting with The Inquirer’s editorial board.

“This is … a 36-year-old incident that has been mishandled for a long time,” he said. “We would like to be the administration that gets to the bottom of everything that happened and put in place procedures and policies to keep it from happening again.”

The nearly 40-minute interview with the mayor and members of his staff represented one of the most expansive explanations about the tumultuous week for his administration, which included Health Commissioner Thomas Farley’s confession that he authorized the quiet cremation and disposal of MOVE victims’ four years ago — an admission that led to his ouster — and then the discovery of those remains intact in a basement office on Friday.

Kenney noted he was in his 20s when the police standoff with the West Philadelphia activist group led to the bombing and fire that killed six adults and five children and destroyed scores of surrounding homes.

“We want this thorough and final,” Kenney said. “And then we also want to figure out a way to kind of deal with this heartbreak and this sin of Philadelphia that’s never been dealt with directly or in an appropriate way as it relates to the death of these Philadelphians at the hands of the government and the death of these children.”

The decades since have brought multiple inquiries, including the work of the MOVE Commission, a grand jury probe, and a long civil trial. The city’s new investigation will defer to the previous commission’s report for details of the bombing, and will only focus on the handling of victims’ remains, said Deana Gamble, a spokesperson for Kenney.

The mayor would not commit to a timeline for the investigation, which will be run by the Dechert law firm and include a lawyer representing the relatives of MOVE victims. But among the new details he did disclose Tuesday was that the cardboard box discovered in a refrigerated area Friday contained 11 different specimens and included both bone fragments and pieces of organs.

It was unclear whether the remains belonged to a single victim or multiple victims, he said. But the words MOVE and save had been written on the box. Kenney did not say who wrote them or why, but he did say how the box came to be found: by an employee in the Medical Examiner’s Office who had been on vacation when Farley resigned but returned to work Friday.

“She told the medical examiner, ‘I do believe I think I know where that box is,’ and went and retrieved it,” he said.

Gamble said it is still unclear why Farley’s 2017 order to dispose of the remains was not followed. “It’s a critical question we aim to uncover during the investigation,” she said.

One of the specimens was marked with the name of a victim, Kenney said. The rest were labeled with letters that City Solicitor Diana Cortes said appear to correspond to folders of documents that were found in the second box, but city officials are not yet sure what the letters represented.

(Mike Africa Jr., a relative of the MOVE victims, told The Inquirer later Tuesday that the family had reviewed a box of documents related to the handling of the remains. He declined to discuss what he learned, except to say, “It’s much, much worse than we thought.”)

Jim Engler, Kenney’s chief of staff, said the investigation will also lead to changes in the Medical Examiner’s Office.

“How do we put in place policies and practices going forward that are going to make us an example that we want to stand up to people?” he said. “Because obviously right now both the city and the medical examiner are not that.”

Medical examiners typically keep small samples from an organ or other tissue from an autopsy after returning the body to the family or a funeral home, Kenney said. In Philadelphia, as in other medical examiner’s offices, those tissue samples are typically cremated and disposed without notifying relatives.

Kenney said the city will determine whether it is possible to have a policy of returning all remains to relatives. “We might be the only Medical Examiner’s Office in the future that actually returns all the remains to the family,” Kenney said.

The city’s investigation will also look at how and why remains were handed over to other institutions.

The University of Pennsylvania has launched its own investigation, after disclosing that the remains of one child victim had been shuttled between it and Princeton University, and even used in classes. The Penn Museum has arranged to return the bone fragments.

The Dechert-led investigation will now “be conducted in coordination with the investigations also underway by Penn and Princeton, Gamble said.

Farley had said in a statement last week that it was the news from the universities that made him reconsider and acknowledge his 2017 decision to order the remains destroyed. .

Even after learning about it, the mayor said, he never spoke directly with Farley about the matter, in part because he was angry. “I didn’t think there would have been a benefit for me at that particular point in my emotion to have that conversation,” he said.

Kenney said the deaths of the five children and the mishandling of their remains have bothered him the most in the last week. On Tuesday, he choked up while discussing it.

“I, the first couple nights, stayed up looking at the ceiling thinking about those kids,” he said. “And somebody told me that they believe that one of the explanations of all of this is that all of those folks are not at rest and have still been not at rest since the time they were killed. And that somehow we have to bring them to a point of rest and we’re going to do our best to do that.”

Africa said Kenney cried during his meetings with the family last week, and said he “would like to believe that his tears were genuine” and that Kenney’s desire to show sensitivity to the family is sincere.

“But given the track record of the city I can’t have any faith in that,” he said.

Staff writers Sean Collins Walsh and Craig McCoy contributed to this article.