"We need to understand the detail and we will draw conclusions and discuss the findings," said Murray.
He said the crew of the Swedish entry Artemis were performing a turning manoeuvre in 18-20 knots of wind when the capsize happened, causing the boat to break into pieces.
"It appears he was trapped under the solid sections of the yacht out of view, out of sight to the myriad people on board trying to locate him, including divers with proper apparatus," added Murray, who appeared close to tears during a news conference on Friday.
"All the crews had been trained underwater, they all carried oxygen and were prepared for the worst. Andrew was located eventually and administered with both care and support on the boat, on the chase boats and later at the docks at St Francis Yacht Club.
"Unfortunately they were unable to retrieve him and he passed."
Another sailor, Olympic bronze medallist Craig Monk of New Zealand, injured his neck but his injury was not life-threatening.
The new-generation America's Cup yachts are hugely powerful 72ft catamarans with solid 'wing' sails able to reach very high speeds.
Defending champions Oracle, who instigated the move from traditional monohulls to make the sport more exciting for spectators, capsized in San Francisco Bay in October 2012, though no-one was seriously hurt.
Sailors wear helmets and body armour and carry knives to cut themselves free from rigging, and also wear small oxygen bottles in case of being trapped underwater. Murray said the organisers were constantly reviewing procedures.
Iain Murray, America's Cup CEO: "It's hard to believe he's gone"
"These America's Cup boats are new, they're very high powered and the loads on them are huge," said British Olympic sailing team chief Stephen Park.
"That brings with it the excitement they were looking for in the America's Cup but these boats are untrodden waters for sailing. A lot of the loads and a lot of the equipment is new and there are a lot of unknowns and things being tested."
Stephen Barclay, chief executive of the America's Cup Event Authority, said he could not rule out delaying the 4 July start of the Louis Vuitton Cup series, which determines the challenger to take on Oracle in the America's Cup proper.
"Nothing is off the table," he said. "We need to know what happened."
He added at the news conference: "These guys are the best, Andrew was the best, top of his game, that means they push, they push hard, second is not good enough.
"In any sport there are incidents when people push themselves and their apparatus to the limits.
"In this case it ended with a fatality and we need to find out why."
Simpson represented Great Britain at two Olympic Games, sailing in the Star class alongside Iain Percy. The pair took gold at the Beijing 2008 Games and silver at London 2012.
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