The phrase "again mentioned that" is correct and usable in written English.
It can be used when referring to something that has been previously stated or discussed, emphasizing that it is being brought up once more.
Example: "In the meeting, she again mentioned that the deadline for the project is approaching quickly."
Alternatives: "reiterated that" or "brought up again that".
They then lost touch until three months ago, when Mateen made contact again, mentioned that he would be in Orlando soon and suggested meeting for a drink.
In 1919 he transferred to Princeton University, and never again mentioned that he attended NYU for a year, presenting himself exclusively as a Princeton man.
To the question on how and to which extent the expert opinions could be used in the policy process, it was again mentioned that it is a good starting point for more in depth analyses.
In 116 years of modern Olympics, Great Britain has won 236 gold medals, Australia 142. Technically, three of Australia's golds came whilst competing under a shared banner with New Zealand as Australasia in 1908 and 1912, but we're happy to never again mention that whole sordid chapter.
Haldeman again mentions that Bernstein is kissing people on the mouth, "including the big black guy" (Alvin Ailey).
Harwood pressed Jordan again, mentioning that he wasn't hearing Jordan say Ryan was essential to achieving the goals he and other House Republicans want.
And, again, Jeff Tester mentioned that word as well earlier this afternoon, the notion of trade-offs.
The same friend mailed again, and mentioned "that time you ran across the square to get the last picnic table ahead of the group walking in front of us".
Just last week, he again mentioned to me that one of his big ambitions in the game is to become the Republic of Ireland manager.
In 1950, the Daily Worker again mentioned Williams, noting that he was among a group of " 'top show business cultural names' . . . who had been assembled to speak on a radio show condemning the jailing of the 'Hollywood Ten,' " and adding, "This radio show was refused by the major networks".
And he once again mentioned deflation -- the fact that prices could fall -- although he did not indicate that deflation was an immediate concern.
