The Japanese media didn't hesitate to release a name, of course. Interestingly neither did "Stars & Stripes":

"Blake Allen Dequaine, 20, was in the custody of Kanagawa Prefectural Police on Tuesday, a police spokesman told Stars and Stripes by phone that day."

https://www.stripes.com/branches/marine_corps/2023-10-03/marine-assault-arrest-japan-11576543.html

https://www.daily.co.jp/society/national/2023/10/03/0016878789.shtml?pg=2