A 25-year-old transgender man died of his wounds in hospital on Friday almost a week after he was assaulted while rushing to help women at a Pride parade in the western German city of Muenster, police said.
The man, whom police have named only as Malte C. in accordance with privacy conventions, intervened when the attacker started hurling homophobic slurs at other participants in the Christopher Street Day parade, police said.
The attacker hit Malte twice in the face. He lost consciousness after his head struck the floor when he fell, and never woke up.
Police said on Friday that they had detained a 20-year-old man whom they suspected of being the attacker.
Politicians and civic groups reacted with shock.
"This terrible event shows that we still have more to do to push for equality and acceptance for people of different sexual orientations," the city's mayor Markus Lewe said, according to broadcaster WDR.
A memorial ceremony was due to be held in the city on Friday evening.
(Reporting by Thomas Escritt; Editing by Andrew Cawthorne)