"Mr. Blumenthal said he did not provide the information to reporters, was unsure how it got into circulation and was 'astonished' when he saw it in print," Hernandez wrote.
But there's evidence that Blumenthal was actually on the team, even if he wasn't captain.
The Yankee Institute for Public Policy dug through Harvard yearbooks and found a photo of Blumenthal at a swim meet with Princeton in 1964, Blumenthal's freshman year.
The institute's director noted, however, that he didn't appear in the team's official yearbook photo.
Blumenthal's campaign manager told the Hartford Courant that her boss was on the freshman swim team.
The Courant also talked with a Connecticut man who was named captain the year after Blumenthal graduated, who said Blumenthal was on the team and "was actually a pretty good" freestyler.
And an unearthed Harvard Crimson article mentions Blumenthal in a story about an intramural swim meet. (Side note: The team was reportedly swimming sans trunks, scaring off the one spectator who came to watch.)
The Times stuck by its story in a statement to the Courant.
"There is no record, according to the Harvard athletic dept records, of Blumenthal being on the team - never getting a varsity letter, never being captain,'' the spokesman said in an email. "In the past, Harvard had club teams and house teams (sort of intramurals) but that is not the Harvard swim team."
It's unclear whether Blumenthal ever said he was captain of the swim team. The author of a Slate profile that said so, David Plotz, told NPR that he never spoke to Blumenthal, saying he relied on earlier media coverage.
The author of the other story, published in the Courant, said she didn't remember whether Blumenthal confirmed that he was captain.
"I looked in the Courant files and read the Slate article,'' she said. "If it was in our paper, I probably I would have felt comfortable with it."
There were also two older profiles -- one in 1980 and one in 1978 -- that described him as captain, according to the Courant.
It's not to say Blumenthal had no hand in the misinformation. As with the dozens of stories that said he served in Vietnam (he served in the Marine Reserves but was never deployed), he never reached out to correct them.