Hersh wrote an article that broke through on Abu Gharib after several other outlets and the Red Cross had already been raising the alarm. His article was important and impactful but "breaking" is really overstating his impact there..
Edited to add a timeline rather than the wall of text;
* June 2023, Amnesty International calls out Abu Gharib as the site where US troops are holding Iraqis without charge in questionable conditions and reports on a riot there that resulted in the death of at least 1 prisoner.
* July 2023, Amnesty reports further after interviewing several prisoners of Abu Gharib that coalition forces are torturing prisoners using prolonged sleep deprivation, prolonged restraint in painful positions -- sometimes
combined with exposure to loud music, prolonged hooding and exposure to bright lights.
Amnesty would go on to write dozens more reports about the conditions in the prisons there.
* November 2003, AP writes an article about the terrible conditions faced by prisoners in the largest camps including reports of uprising and shootings at Abu Gharib.
* January 2004, Darby blows the whistle and provides a CD full of images of torture to US Army criminal investigators.
* January 2004, based on Red Cross reports from their inspectors in Iraq, Army commissions Taguba Report to investigate the rampant reports of torture and inhumane conditions in Iraqi prisons. Report was completed in February and found tons of torture.
* February 2004, Amnesty reports on further torture within Iraqi prisons naming specific victims, techniques, and prisons.
* Late April, 2004 First pictures of torture start being released among hints of a secret Army Report.
* April 27, 2004, 60 Minutes publishes report detailing the abuse and publishes several pictures from Darby's disc. Dan Rather names several soldiers who the Army had been quietly court martialing. They had received the report / pictures ~3/4 weeks earlier.
* April 30, 2004, Hersh's New Yorker piece comes out with more details.