The discovery of the wreckage of the ARA San Juan, the submarine lost a year ago, has revived the stalled probe into the cause of the undersea disaster that took the lives of 44 crew-members.
Families of the victims have called for the submarine to be refloated, an enormous undertaking that authorities cautioned was likely beyond their means.
"We're talking about a vessel that, filled with water, weighs 2,500 tons," said the federal judge in charge of the investigation, Marta Yáñez.
Yáñez, based in Caleta Olivia, in Santa Cruz province, said she would not risk raising the submarine "if that means causing it to break up."
"I prefer to preserve the evidence in place," she said.
But she has issued summonses to the naval officers who were aboard the Seabed Constructor when it found the submarine on Friday, a year and a day after it vanished in the South Atlantic with all aboard.
Crushed from an implosion, the submarine was located at a depth of more than 900 metres (3,000 feet) in a desolate area of undersea craters and canyons 400 kilometres (250 miles) off the coast.
An underwater robot sent down by the Seabed Constructor, which specialises in ultra-deep water exploration, relayed 67,000 images of the sunken vessel.
Luis Tagliapietra, the father of San Juan crewmember Ensign Alejandro Tagliapietra, was among those on board the ship when it located the submarine.
"I don't have words to describe it, I feel profound pain and anguish," he said in a brief video carried by local media. "But at the same time we know where they are and it is the first step to learn the truth of what happened."
"It's a very hard day, an inconceivable, unreal day. But it is also the first step, which has taken a year, to reach the truth. We are not going to rest until we know what happened."
Defence Minister Oscar Aguad met Saturday with the families of the victims and showed them photographs of the wreckage, including images of a propeller, the sub's torpedo-launching tubes and an upper section of the vessel lying on the ocean floor. (To see these images, see out story from yesterday.)
"We are all destroyed here," said Yolanda Mendiola, the mother of crewman Leandro Cisneros, 28.
"I still had hopes that they could be alive," Luis Niz, the father of a missing sailor, told reporters, even though President Mauricio Macri's government had declared two weeks after the sub's disappearance that there could be no survivors.
Although an official investigation was opened a year ago, investigators have had little to go on until now.
Nonetheless, Navy chief Marcel Srur was removed from his post in December.
Seabed Constructor, a jewel in the fleet of US-based exploration company Ocean Infinity, was headed Sunday for Capetown, South Africa for maintenance, the Navy said. It currently has onboard four relatives of missing crew-members, who were observing the search from the ship.
From South Africa, the family members will return to Argentina with support from the local Argentine Embassy, the Navy said in its Twitter account.
When repairs are completed, Seabed Constructor will return to the area where the submarine was located.
According to preliminary information released by the Navy, the San Juan imploded two hours after its last communication with the Mar del Plata naval base, its home port, on November 15, 2017. The sound of the explosion was recorded and traced to the general area where the submarine was found.
In a message broadcast, Macri promised to get to "the truth needed to honour and respect our heroes and their families."
"A serious phase of investigation is underway to know the whole truth, a truth to which we've all been committed from day one," he said, announcing three days of national mourning.
"It is a news that delivers us enormous pain, the confirmation of the death of the 44 crew=members in dramatic circumstances. Today is the saddest day," Macri said.
He did not refer to whether a decision had been taken to try and refloat the vessel.
The director of Ocean Infinity, Oliver Plunkett, released a message Sunday in which he expressed to the families his hope that "having located the site where the ARA San Juan brings them comfort. "
"In addition, we hope that our work will deliver them answers and that lessons learned will prevent any similar event from ever happening again," he added.
Families of the victims, staying at the Tierra del Fuego Hotel in Mar del Plata, held a march Sunday in memory of the "44 hearts of steel."