Three young Coast Guardsmen went out for a drink on a chilly morning in Dutch Harbor. One never returned.

On a frigid January night, three Coast Guard seamen too young to drink at a bar walked along the beach in Dutch Harbor, sharing swigs from a bottle of Rich & Rare Reserve Canadian Whisky. But when the sun rose, only two of the Guardsmen returned to their ship safely.

After an hours-long search, Ethan Kelch, 19, was found dead on the western shore of Amaknak Island.

A seven-month investigation led military prosecutors in August to charge and arrest Ethan Tucker, 21, alleging he severely beat Kelch, tried to strangle him, and then dragged him into the ice-cold water and left him to drown. But Tucker was released Monday after his attorney said new evidence, including Snapchat videos shot on the night of Kelch’s death, tells a drastically different story, namely that two men fought valiantly to save their friend before his drowning.

"Tucker frantically tried to keep his friend out of the frigid Alaskan waters," Tucker's military defense attorney, Navy Cmdr. Justin Henderson, told The Washington Post.

Despite his release and some allegations in the case being scrapped, prosecutors say they still intend to prove Tucker murdered Kelch.

Tucker and Kelch, who have been described as “best buddies,” were both seamen assigned to the U.S. Coast Guard Cutter Douglas Munro, based in Kodiak. The ship was in Dutch Harbor, about 830 miles southwest of Kodiak, for repairs, and on Jan. 26 the two friends were enjoying a night off with a third shipmate, Trevin Hunter. After struggling to keep Kelch away from the water for a half-hour, Tucker collapsed on the beach. He was discovered lying in the sand unconscious the next morning, only 200 yards from the spot where Kelch was later found.

In August, military prosecutors alleged Tucker had punched his fellow Coast Guardsman so hard during a drunken fight on the beach that he caused internal hemorrhaging, leaving the 19-year-old with a swollen bump on his scalp. Tucker also tried to strangle his friend in the scuffle, they said. Then he allegedly dragged Kelch into the icy waters and left him to drown, according to a charging document obtained by The Post.

But in October, the San Diego Union-Tribune reported, Henderson brought Snapchat videos recorded by Hunter to a court hearing that he says show Tucker and Hunter fighting to stop their friend from swimming in the dark 38-degree waters. Witnesses testified that Kelch had frequently been difficult to control when drunk, Henderson told The Post, and one witness said he had seen Kelch drink too much at least 20 times.

After wrestling with Kelch for almost 30 minutes as he pushed toward the ocean, Tucker's attorney said, Tucker collapsed on the beach in an exhausted, intoxicated heap, the Union-Tribune reported.

"All the evidence shows that effort, and we trust that a fair trial will vindicate SN Tucker," Henderson told The Post in a written statement.

At that same October hearing, a medical examiner told the court that the physical injuries to Kelch's head, which he probably sustained in the fight with Tucker, were not fatal, the Union-Tribune reported. Cristin Rolf, the state's chief medical examiner who performed the autopsy, said the 19-year-old had died by drowning.

Vice Adm. Linda Fagan, who will oversee the case if a court-martial proceeds, sent the charges back to prosecutors after the October hearing. The military lawyers struck parts of the charges, withdrawing claims that Tucker caused severe injuries by "blunt force trauma" and retracting the allegation that he "placed" Kelch in the water.

Despite the videos that Henderson said show the young men struggling to keep Kelch away from the water, Tucker was charged again with murder, manslaughter and several other charges. If convicted, Tucker could face a possible life sentence and dishonorable discharge, the Coast Guard said in a statement in August.

Prosecutors maintain Tucker lied about the drunken evening when he told officials he had injured his hand by "punching a steel bulkhead" and told rescue teams searching for Kelch to look for him at a spot far from where the men had been drinking the night before. Prosecutors said he tried to "impede" the investigation because he "had reason to believe that there were or would be criminal proceedings pending," according to the charging documents.

On Monday, Rear Adm. Melvin Bouboulis ordered Tucker released from the military prison in San Diego. Tucker will be allowed to work in logistics at Base Alameda in Northern California until his case proceeds, the Union-Tribune reported.

"We will continue to vigorously defend Seaman Tucker against any charge that he caused the death of his friend," Henderson told The Post.

A preliminary hearing is scheduled for Dec. 9, Henderson said.