The phrase "again investigated" is correct and usable in written English.
It can be used when referring to a situation or subject that has been examined or looked into multiple times.
Example: "The case was again investigated after new evidence came to light."
Alternatives: "re-examined" or "further investigated".
In the investigators' similar follow-up study, they again investigated the antibiofilm activity of CAZS (with or without the use of a hydrodebrider) but added an additional assessment of cilia morphology.
Wada themselves have again investigated following the recent articles.
And by the way, that program, again, investigated.
DCS again investigated an allegation that Rogers gave birth to a baby exposed to marijuana.
In 2006, the Italian authorities again investigated money-laundering allegations involving a failed attempt to take over Lazio.
Major League Baseball again investigated -- including unsuccessfully asking the author, Selena Roberts, for her cooperation -- but nothing further resulted.
Furthermore, our earlier cross-sectional and longitudinal instrument-driven investigations [ 26, 33] motivated us to again investigate this group, employing another methodological approach to more fully comprehend the phenomenon of the educational environment.
Late last year, investigators received a tip that moved them to again investigate Mrs. Durst's disappearance.
Google shot back in May with a similar request for the commission to again investigate Microsoft.
In 2011, Imroz went to work again, investigating how India had restored the peace, and I shadowed him.
Reviving a practice hated, feared and ultimately banned in Soviet times, the domestic successor to the K.G.B. has served notice that it is again investigating anonymous accusations of crimes against Russian citizens.
