Plane carrying Cokie Roberts’ father disappeared in Alaska in 1972. It was never found.

Rain fell, clouds hung low in the sky and the air was choppy when Cokie Roberts’ father boarded a plane in 1972 to campaign in Alaska for the re-election of a fellow congressman.

Roberts’ father, then-House Majority Leader Hale Boggs, D-La., met Alaska Rep. Nick Begich at Anchorage International Airport on Oct. 16 to board a chartered Cessna 310 for a 550-mile flight to Juneau, The Washington Post reported. Both congressmen’s wives had considered joining the trip, but decided they had too much to do in D.C.

Despite low visibility, the plane took off at 9 a.m., flew through Portage Pass and along the snow-capped Chugach Mountains. The control tower last heard from the pilot at 9:12 a.m.

When the phone rang a few hours later at the Begich household in McLean, Virginia, Alaska Gov. Bill Egan was on the line. Begich's wife, Pegge, immediately knew something was wrong.

"I just had an awful feeling in the pit of my stomach," she told the Post.

As authorities searched for the missing plane, Boggs’ wife, Lindy, invited the Begiches to their home in Bethesda, Maryland, the next day for a private Mass celebrated by Boggs’ brother Robert, who was a Jesuit priest. The families received various reports that potential debris had been discovered, but none of it turned out to be the congressmen’s plane.

At Pegge Begich’s urging, the Boggs family decided to go to Alaska while the search continued. Roberts, who died Tuesday at the age of 75, was reluctant. Then 28, she had two young children and a TV news job in California.

[Cokie Roberts, pioneering national political journalist, has died at 75]

“If you were missing in Alaska,” Lindy Boggs told Roberts, “Daddy would go looking for you.”

Over the next 39 days, the Boggs family got regular briefings and photos from spy planes based at Elmendorf Air Force Base in Anchorage. Hunters, boats and more than 70 airplanes joined in the search, which was the largest in Alaska's history at that time. They found another plane that had been missing for 17 years, but they never recovered the congressmen's aircraft.

The conspiracy theories surrounding the disappearance mounted: Maybe a bomb had exploded on board, or perhaps Boggs' role in the Warren Commission - charged with investigating the 1963 assassination of President John F. Kennedy - had something to do with the disappearance.

Boggs had expressed doubts about the commission’s majority opinion that Kennedy and Texas Gov. John Connally were struck by a single bullet and therefore there was just one assassin.

In a note forwarded to Pegge Begich from her husband’s office, scraps of newsprint from the Detroit Free Press spelled out another theory about the politicians’ disappearance: His Croatian heritage and his support of Croatian nationalism might have gotten him assassinated by Serbians, the note said. Both ethnic groups were common in Yugoslavia at the time, and tensions ran high.

Boggs and Begich, both Democrats, were re-elected the November after their disappearance, although they had not been found. On Jan. 3, 1973, however, the House of Representatives recognized the congressmen’s deaths.

Lindy Boggs competed in a special election to fill her husband’s seat. She won and went on to serve for nine terms. President Bill Clinton later appointed her the U.S. ambassador to the Vatican.

The missing congressmen, meanwhile, eventually got a cenotaph at Congressional Cemetery in southeast Washington.

Roberts told The Post in 1977 that her mother wanted them to have a monument.

“She thought that would be a good idea for Daddy and Nick Begich, because they were never found and couldn’t be buried. Daddy’s plaque is on one side of it, and Nick Begich’s is on the other side. So it’s like they are together for eternity.”