A new report nearly one year after Hurricane Maria shows the storm is officially the most deadly U.S. natural disaster in the last century. Puerto Rico's government requested an independent review by George Washington University, which found Maria killed an estimated 2,975 people – more than 46 times the original official death toll of 64.

For months, there's been speculation the death toll was much higher than what the government was reporting. San Juan's mayor, Carmen Cruz, called the new report "painful and shameful," and told CBS News' David Begnaud the governor should take more responsibility.

"When I saw people dying I opted to shout it. I opted to ask for help. When others saw people dying they opted to shut up," Cruz said.

Puerto Rico Gov. Ricardo Rosselló acknowledged Tuesday that he made mistakes.

"The focus shouldn't be, you know, hey, let's blame all these folks. The focus should be who's going to be accountable and who's going to take the action so this doesn't happen again," Rosselló said.

Researchers found the government and hospitals were inadequately prepared for the Category 4 storm. They also found the risk of death was 45 percent higher for those living in low-income areas on the island, and elderly men were at the greatest risk of dying.

But previously healthy young people, like 29-year-old Rom-zee Romero, also died. His brother, Christian, told us Rom-zee contracted a treatable bacterial disease after helping his community clean up from the hurricane. He was in and out of overwhelmed hospitals before succumbing to his illness.

"I think the government was negligent," Christian told us. He says his brother deserves justice.

Nicole Cordero says her 47-year-old mother, Wanda, indirectly died as a result of Maria. Wanda had pancreatitis and needed oxygen when the power went out at her hospital.

"I wish the hospitals were more prepared," Cordero said.

Researchers say many physicians here didn't know how to properly report hurricane-related deaths after the storm, which is why the initial death toll was so low. President Trump has not commented on the new numbers directly. The White House said Tuesday it's focused on Puerto Rico's recovery and preparedness for this hurricane season.