When the RMS Titanic went down on the night of April 14-15, 1912, people on both sides of the Atlantic frantically awaited further news. An official investigation wasn't far off, but during the immediate aftermath, solid intelligence about the tragedy was hard to come by.

The newspapers pieced together what little information they could obtain from wireless telegraph messages sent by the Titanic and other ships at sea, often relying on speculation to fill the gaps. More than one major paper assured readers that all the passengers had been saved and the wounded liner was slowly making its way to Nova Scotia. It wasn’t until the rescue ship Carpathia arrived in New York on April 18 that fuller details began to emerge. Even then, rumors were rampant.

Fortunately, for the sake of history, government officials in both the United States and Great Britain moved aggressively to find out what had happened and why. Their inquiries, beginning on April 19 and May 2 respectively, put on record much of what the world now knows about the disaster—that the ship was traveling too fast for the icy conditions, that its design made it more vulnerable to sinking than anyone realized, that it was carrying far too few lifeboats for the people onboard and much more.

Sen. William Alden Smith (R-Mich.), a lawyer by training, led the U.S. Senate inquiry. He wasted no time in rounding up key witnesses, in part out of concern that they would leave the U.S. and return to England before they could be questioned. Smith and his entourage met the Carpathia at its New York dock to serve subpoenas on the surviving members of the Titanic’s crew, the Carpathia’s captain and J. Bruce Ismay, chairman of the White Star Line and a survivor of the wreck.

The inquiry began the next morning at a New York hotel before moving to Washington, D.C. a few days later.

Smith would call 82 witnesses in all, including four Titanic officers, 34 crew members and 21 passengers. Their eyewitness accounts testified to the ship’s reckless speed, the captain’s apparent indifference to iceberg warnings sent by other ships, the crew’s ill-preparedness in handling lifeboats and, most damningly, a mysterious nearby ship that refused to come to the Titanic’s aid despite seeing its distress rockets. Smith pointed the blame at the freighter SS Californian and its captain, Stanley Lord, whom he also subpoenaed and treated to a vigorous grilling.

The report Smith’s subcommittee issued on May 28 was praised for its detail and remains an essential document for Titanic historians to this day. His behavior, however, was another matter. A London paper accused him of “browbeating, bullying and baiting” witnesses—particularly Ismay, who, in saving himself, had become a villain in the American press. Newspapers around the world called out Smith’s lack of nautical knowledge and ridiculed many of his questions to the Titanic’s crew, most famously: “Do you know what an iceberg is composed of?” (To which Titanic Fifth Officer Harold G. Lowe replied, “Ice, I suppose, sir.”).

But The New York Times, which did its share of mocking Smith, acknowledged that, for all his faults, “he has brought out what we all wanted to know and had a right to know about the loss of the big ship” and “enabled us all to form a clear idea as to where the responsibility, direct and indirect, for that loss lies.”

Smith’s report may also have served another purpose. As one American magazine observed, the testimony Smith had put on record made it all but impossible for the British inquiry to simply whitewash the disaster, as many feared it would.

The second major inquiry, which began about two weeks after the sinking, was conducted on behalf of the British Board of Trade—a body that Smith had harshly criticized, saying its “laxity of regulation and hasty inspection” was a major cause of the disaster.

Chosen to lead the court of inquiry was Lord Mersey, otherwise known as John Charles Bigham, a lawyer with experience in shipping cases.

“What was to surprise many observers, but not those who knew Lord Mersey well, was the surprising objectivity that the court was to display during the next five weeks,” writes Titanic historian Daniel Allen Butler in his 2009 book about the disaster and its aftermath, The Other Side of the Night. Even the Board of Trade, Butler adds, “would not escape Mersey’s keen eye or sharp tongue.”

Mersey also had the benefit of the evidence amassed by William Alden Smith’s subcommittee. When his personal papers relating to the Titanic—including his private notes on the inquiry, which will be explored on the HISTORY show "History's Greatest Mysteries"—their contents included two copies of the American report.

Mersey’s court of inquiry called 97 witnesses and issued its report at the end of July. While it covered much the same ground as the American report, “the British investigators paid far less attention to the human facets of the disaster and focused more exclusively on nautical and navigational matters,” writes Wyn Craig Wade in his 2012 book, The Titanic: Disaster of the Century. “How the Titanic was damaged and subsequently flooded was covered in considerable detail.”

The British report disappointed some observers, who expected the Titanic’s captain, E.J. Smith, to be more harshly criticized for failing to reduce speed. It absolved him of negligence but admitted he had made a “very grievous mistake.” J. Bruce Ismay got off the hook, as well, the report concluding that, “Had he not jumped in [the lifeboat], he would merely have added one more life, namely, his own, to the number of those lost.”

Captain Stanley Lord wasn’t so lucky. If anything, Mersey gave him a more thorough working over than Smith had. In the final report, he concluded that, “When she first saw the rockets, the Californian could have pushed through the ice to the open water without any serious risk and so have come to the assistance of the Titanic. Had she done so she might have saved many if not all of the lives that were lost.”

(More recent investigations, based on the location of the Titanic’s wreckage, discovered in 1985, have concluded that the Californian was too far away to have saved many, if any, lives. Some historians still fault Lord for taking no action to aid a ship in distress, while defenders maintain he was blameless.)

The British inquiry’s major contribution may have been its list of 24 recommendations for making sea travel safer. While the American report had made similar recommendations, the powerful British shipping companies seemed more likely to take them seriously, coming from their own government.

The recommendations included providing a sufficient number of lifeboats; adequate training to crew members on how to handle them; greater government authority over the design of ships and their watertight compartments; the installation of wireless telegraphs on all ships; and the hiring of enough operators to staff them around the clock. Many of those recommendations became part of international maritime law in 1914.

As to the two very different men who’d led their countries’ inquiries, both Smith and Mersey moved on to other projects. But for Mersey, the Titanic inquiry proved to be valuable preparation. In 1915, he would lead the investigation into another sea disaster that riveted the world: the sinking of the RMS Lusitania.