I found it (by googling in Dutch rather than English). In English, the atrocity is referred to as the Bunker Tragedy, as summarised by Wikipedia:
The Bunker Tragedy or the Bunkerdrama was an atrocity committed by the staff at the Herzogenbusch concentration camp (also known as Kamp Vught) in the Netherlands, in January 1944 during World War II.
When one woman from barrack 23B was locked up in the camp prison (the 'bunker'), other women protested against it. Commander Adam Grünewald, as a punishment, had as many women as possible incarcerated in one cell. Eventually, 74 women were pressed together in cell 115, which had a floor area of 9m² and hardly any ventilation. After 14 hours of confinement, the inmates ere released from the cell. Ten women did not survive the night.
The incident soon became known outside the camp and was written about in resistance newspapers. The occupying power was not pleased with the fact that the news had leaked. The commander was demoted to the ranks and was sent to the Eastern front, where he was killed in combat.
More details are available on the website of the museum Kamp Vught, albeit in Dutch. The remainder of this answer is an abridged version of what is told in this source. It is also the topic of a radio documentary from 15 November 1987 (in Dutch) and a book published in 1995.
According to the museum, Commander Grünewald had been appointed to make Camp Vught a model camp. In Nazi Germany, model camps were punishment/labour camps where circumstances were less bad than in other camps, serving propaganda purposes. One of the prisoners, Jedzini, betrays other prisoners by telling guards that she overheard others discussing how they can once again help people into hiding after they are released. The other prisoners find out and decide to punish Jedzini. Thea and Non Breman cut off Jedzini's hair. The next day, Grünewald hears about this incident and puts Non Breman into solitary confinement. 89 women decide to declare solidarity with Non. What happens the following night is not entirely clear, but Jedzini goes outside (perhaps to escape more punishment by fellow prisoners?), is shot by a guard, and ends up in the infirmary. The following morning, camp guards receive a list with the names of all the women who declared solidarity. Suze Arts, a Dutch woman working in the camp as a guard, is tasked with gathering all the 89 women on the list just before her weekend off. She has always denied knowing what happens next.
Grünewald puts as many of those 89 women as he can into the same 9m² prison cell as Non Breman. He manages to fit 74 women in there, the other women are put in another cell. The situation in the cell is terrible, the women are breaking the one tiny window to get some air, but many faint due to the heat and lack of oxygen. Ten women die.
The next morning, the camp doctor ignores Grünewalds commands and treats the survivors against Grünewalds orders, distributing them with five women per cell and providing mattresses, food, and drink.
Thea Breman was scheduled for release and is released according to plan.
Suze Arts, on her weekend off, is called in to the Sicherheitsdienst to describe what happened. The camp doctor writes a letter to Berlin with his testimony, and the telephonist Eva travels to The Hague to describe the same. The underground newspaper Trouw (today one of the main daily newspapers in The Netherlands) reports on the incident, but does not know much about the details. Days later, thousands of people write protest letters to the Sicherheitsdienst. Himmler travels to Vught, an SS court convicts and demotes Grünewald. Vught was supposed to be a model camp, and this atrocity does not fit in this image. Himmler revokes the conviction, because he says that if Grünewald is convicted for this then every SS member in The Netherlands is at risk of conviction. Nevertheless, he is moved to the East Front; although technically not a demotion, he dies in combat there. Jedzini dies from her wounds. The camp doctor is promoted. After the war, Suze Arts is convicted to fifteen years in prison by an extraordinary Dutch court.
Reading the details, it is less clear to me how important the press leak was. It seems that this is topic of some historical debate. What was the role of Trouw in spreading information to the thousands of people who wrote protest letters? Would Grünewald have been demoted and moved if news had not spread? I find it an interesting detail that Thea Breman was released, did she tell the underground press? I suppose those questions may never be fully answered, but the atrocity gives some insight in both life in Kamp Vught, the spreading of news under the occupation, and in the handling by the SS and the SD regardless.
Further reading/listening (all in Dutch)
- Hans Olink. Vrouwen van Vught (1995): Een nacht in een concentratiekamp. Amsterdam : Bas Lubberhuizen. 122 pages. ISBN 90-73978-35-1
- Het 'Bunkerdrama' in Kamp Vught: radio documentary broadcast 1987-11-15. Listen online via VPRO
- Online summary at the website of the Nationaal Monument Kamp Vught