SAN JUAN, Puerto Rico — A team of George Washington University researchers will lead an independent investigation into Hurricane Maria’s death toll in Puerto Rico and will examine the methods local government officials used to count hurricane-related fatalities in the aftermath of the September storm, officials here said Thursday.

Puerto Rico announced in December that the official number of deaths attributed to Hurricane Maria was 64, a number that independent analysts have said is a severe undercount. Some estimates say that the hurricane’s lingering effects — long-term loss of power, lack of health care, inaccessibility in some remote areas — have led to hundreds of deaths and heavy criticism of the official tally. At least one lawsuit seeks mortality data from the local government.

“I want to know the truth of the number the same as you do,” Gov. Ricardo Rosselló said at a news conference here Thursday, saying that there was no effort to intentionally downplay the death count. “We want to get as close as the most accurate number as possible.”

The U.S. territory was plunged into complete darkness and many areas were cut off after the tempest’s 155-mph winds lashed the island in mid-September, collapsing the power grid and telecommunication networks. The meltdown hobbled the federal and local government’s emergency response, leaving hundreds of thousands cut off from food, clean water, medicine and electricity needed to power lifesaving medical equipment. Power has not yet been restored to parts of the island.

Puerto Rico’s government is funding the first phase of the $305,000 review, but the group is seeking grant funding to study the process local officials undertook and plans to make recommendations to better understand deaths that are related to natural disasters. They hope the findings will help prevent fatalities in future storms.

Lynn Goldman, dean of George Washington’s Milken Institute School of Public Health, said that within three months, the research team led by epidemiologist Carlos Santos-Burgoa will be able to determine an approximate death toll.

“We will call it as we see it, I promise,” Goldman said.

Santos-Burgoa, a former public health minister in Mexico who oversaw the response to the 2009 H1N1 flu outbreak, said he will work with researchers and demographers in collaboration with the University of Puerto Rico to collect data from government sources, death certificates, official demographic statistics and news reports.

Hundreds of death certificates had to be completed by hand by local officials during telecommunications and power outages, in many cases attributing potentially hurricane-related deaths to natural causes. Goldman said some of those documents will make clear the underlying causes of death, but she expects there will be many cases that researchers will need to investigate further to determine the cause and circumstances.

Santos-Burgoa cautioned that there always will be a degree of uncertainty surrounding the final estimate of the death toll. Counting deaths related to a hurricane or other natural disasters often is a subjective exercise, and tallies sometimes include people who died while preparing for a storm’s arrival or of natural causes afterward that can’t be linked to the storm itself.

“How precise will it be? We shall see,” he said. “All of our work will be made public.”

The scientists plan to deliver their first report within 90 days and full findings within a year. They expect to publish a warehouse of mortality records for the public to peruse, and the group plans to submit its work to peer review.

Questions surfaced shortly after the government of Puerto Rico released early death toll numbers in September as the island-wide power outage dragged on; the governor ordered a recount in December. Members of Congress, concerned that the Rosselló administration was suppressing the number, asked the Government Accountability Office to audit the territorial government’s methodology. GAO spokesman Charles Young said the agency’s work won’t begin for several months.