An American cruise company says it deeply regrets that one of its ships sailed past dying men aboard a fishing boat adrift in the Pacific Ocean.
Two of the three Panamanians on board the disabled vessel died of thirst after the failed distress call.
Princess Cruises said that although passengers had spotted the castaways and alerted staff, the captain had not received the message.
The one survivor - Adrian Vasquez, 18 - was later rescued after 28 days at sea.
Mr Vasquez and his friends set out in their three-metre-long open fishing boat the Fifty Cents from the port of Rio Hato in February, and were on their way back after their catch when the engine failed.
After 16 days adrift, he says, they saw a cruise ship sailing past, and had made attempts to flag it down with a red sweater. "We felt happy, because we thought they were coming to rescue us," he said.
Three birdwatchers on board the cruise ship - the Star Princess - said they had spotted the fishermen waving for help and told ship staff, but had been unable to persuade them to change course.
The crew member they told said he would tell the bridge, but the ship sailed on.
In a statement, Princess Cruises said a preliminary investigation had found that there appeared to have been a "breakdown in communication" in relaying the passengers' concern.
It said the captain - Edward Perrin - and the officer of the watch were not notified.
"Understandably, Capt Perrin is devastated that he is being accused of knowingly turning his back on people in distress. Had the captain received this information, he would have had the opportunity to respond."
Princess Cruises added that it understood its responsibility under the law of the sea to help any vessel in distress, and said its ships had been involved in more than 30 rescues over the past decade.
It said the investigation was continuing.
Mr Vasquez was eventually rescued 1,000km (620 miles) off the mainland, near the Galapagos Islands. His friends had already died of thirst.
He said he survived thanks to a sudden rainstorm that replenished his drinking water supplies.
He told the Associated Press he still felt anger at the ship he saw sail past two weeks before his rescue.
"I said 'God will not forgive them'. Today, I still feel rage when I remember."
Birdwatcher Jeff Gilligan, the first to see the boat, described the episode as "very disturbing" and said he could not understand what had happened.