Federal authorities are investigating the death of an endangered Hawaiian monk seal that witnesses said they believed was shot as it lounged on a beach on the North Shore of Kaua'i yesterday.

The National Oceanic & Atmospheric Administration's Fisheries Service confirmed last night that it retrieved the carcass of a monk seal yesterday. But spokeswoman Wende Goo said the cause of death won't be determined until a necropsy is performed.

Goo said the dead seal was a female, but declined further comment.

This is the second monk seal found dead on a Kaua'i beach in the past month. On April 19, a 4-year-old male seal was discovered dead, and Goo said that case remains under investigation.

Goo would not confirm two witness accounts that the monk seal that was found yesterday had been shot.

But a Kaua'i couple told The Advertiser that they think the seal was shot to death. The couple, who did not want their names revealed because they feared retaliation, said they had just arrived at the Pila'a Beach area at about noon and were standing on a hillside above the beach when they spotted the seal lying on the sand.

As they began to head down a trail to the beach, the two said they heard loud noises that they thought were gunshots. They then saw the monk seal as it scampered toward the ocean.

At that time, the two said they saw a man standing next to a white pickup truck. although they didn't see a weapon. The couple said they did not see anyone else in the area.

When the couple got to the beach, they talked briefly with the man, but did not notice anything unusual.

"We didn't (initially) think that the monk seal had been shot because it swam away, that maybe it heard that loud noise and got scared and ran away," the male witness said.

After about 45 minutes, the witness said he and his wife saw the seal in the surf and waited to see if it would return to shore so they could photograph it. But the man said they quickly realized that something was wrong.

"After watching it, it was kind of just flowing with the current and wasn't breathing and sticking its head up and (we) realized it might be dead," he said. "It washed up on shore and we realized that it was bleeding out of its side and its mouth."

The female witness said she saw one "perfect little puncture wound" on the side of the seal, about two feet from its tail. She said she had heard what appeared to be four gunshots, although she didn't see more than that single wound.

The couple called state Department of Land and Natural Resources officials and later NOAA authorities.

The woman said she was bothered by the apparent senseless killing of the monk seal.

"There's no point. He didn't drag it off to eat it," she said. "If the seal was shot, it was out of some kind of sick game."

Hawaiian monk seals are one of the most endangered species in the U.S., with fewer than 1,300 remaining. They are protected under the Endangered Species Act, Mammal Protection Act and state wildlife laws.