SURFSIDE, Fla. (NewsNation Now) — A 12th victim was found in the rubble of the collapsed condo building in Florida, Miami-Dade County Mayor Danielle Levine Cava confirmed Tuesday night. The slow work of sifting through the remnants of the condo building stretched into a sixth day Tuesday, as families desperate for progress endured a wrenching wait for answers.

As of Tuesday night, 149 people are still missing, while 125 people have been accounted for, not including the 12 deaths.

“We have people waiting and waiting and waiting for news,” Levine Cava told reporters. “We have them coping with the news that they might not have their loved ones come out alive and still hope against hope that they will. They’re learning that some of their loved ones will come out as body parts. This is the kind of information that is just excruciating for everyone.”

State Attorney Katherine Fernandez Rundle said earlier Tuesday that prosecutors will pursue a grand jury investigation into the collapse of the oceanfront condominium building.

“I am going to urge them to take a look at it,” Rundle told the Miami Herald. “Whether they do or not, it’s completely their decision.”

Grand juries in South Florida have examined other large-scale disasters, such as the 2018 collapse of a pedestrian bridge at Florida International University, which killed six people. That investigation is ongoing.

Those at the scene tell NewsNationNow.com the rescue crews are anxious to find someone they might be able to help. “It is frustration and it is a little bit draining just to feel you have all of these skills, you have an amazing team of people, you have excellent resources, and there is no one on which to use them,” Dr. Howard Lieberman with Jackson Memorial Hospital said.

Families, who’ve been gathered for six agonizing days, are trying to hold on to the hope that brought them there.

“I understand the odds against us, however myself and my family are not ready to give up,” Rachel Spiegel said as she waits for word about her mother, Judy. “We’re not ready. I’m pulling my strength from the love I have from my mom, the love my kids have for my mom, and my poor dad – the best husband in the world.”

“There is hope,” said Martin Langesfeld. His sister is missing. “I really believe miracles do happen. Things like this have happened around the world and forces. Israeli forces. Mexican forces. The best teams are on this mission right now. I truly believe.”

The town of Surfside has a population of just over 5,000. The area is a mix of new and old apartments, houses, condominiums and hotels, with restaurants and stores serving an international combination of residents and tourists. The community provides a stark contrast from bustle and glitz of South Beach with a slower paced neighborhood feel.

Authorities are meeting frequently with families to explain what they’re doing and answer questions. They have discussed with families everything from how DNA matches are made to help identify the dead, to how will next of kin be contacted, to going into “extreme detail” about how they are searching the mound, the mayor said.

Armed with that knowledge, she said, families are coming to their own conclusions.

“Some are feeling more hopeful, some less hopeful, because we do not have definitive answers. We give them the facts. We take them to the site,” she said. “They have seen the operation. They understand now how it works, and they are preparing themselves for news, one way or the other.”

Rescuers are using bucket brigades and heavy machinery as they work atop a precarious mound of pulverized concrete, twisted steel and the remnants of dozens of households. The efforts included firefighters, sniffer dogs and search experts using radar and sonar devices.

Miami-Dade Fire Rescue Chief Alan Cominsky said first responders have moved nearly three million pounds of concrete and are using sonar and video equipment to search for any signs of life in the rubble.

“This is a very tedious effort,” Cominsky said. “It’s methodical, very difficult process. As we’re removing debris, we’re just finding more debris that’s just, concrete pulverized. It’s extremely difficult.”

Authorities said their efforts were still a search-and-rescue operation, but no one has been found alive since hours after the collapse on Thursday.

The White House confirmed in a statement Tuesday that President Joe Biden will visit the Surfside building collapse Thursday.

Biden has offered federal help and extended his concerns to the community as people “grieve their lost loved ones and wait anxiously as search and rescue efforts continue,” as he said in one tweet.

The pancake collapse of the building left layer upon layer of intertwined debris, frustrating efforts to reach anyone who may have survived in a pocket of space.

“Every time there’s an action, there’s a reaction,” Miami-Dade Assistant Fire Chief Raide Jadallah said during a news conference. “It’s not an issue of we could just attach a couple of cords to a concrete boulder and lift it and call it a day.” Some of the concrete pieces are smaller, the size of basketballs or baseballs.

Deciding to transition from search-and-rescue work to a recovery operation is agonizing, said Dr. Joseph A. Barbera, a professor at George Washington University. That decision is fraught with considerations, he said, that only those on the ground can make.

Barbera coauthored a study examining disasters where some people survived under rubble for prolonged periods of time. He has also advised teams on where to look for potential survivors and when to conclude “that the probability of continued survival is very, very small.”

“It’s an incredibly difficult decision, and I’ve never had to make that decision,” Barbera said.

The building collapsed just days before a deadline for condo owners to start making steep payments toward more than $9 million in repairs that had been recommended nearly three years earlier, in a report that warned of “major structural damage.”

Reporting by AP’s Russ Bynum. The Associated Press contributed to this report.