Angelo's Stand ability was brought forth by the mysterious bow and arrow, and apparently they're also connected to DIO. After defeating Angelo, Jotaro thought that the danger had left the city, and tries to find the whereabouts of the bow and arrow. A few days later, Koichi is walking home with Josuke, and they pass a house that should be empty...
It was a mystery how he 
obtained his Stand powers.
.فكيفيّة حصوله على قوّة ستاند كانت غامضة
Es war bisher unklar,
woher er seinen Stand bekommen hat.
Cómo obtuvo su Stand
había sido un misterio hasta ahora.
Cómo había obtenido su Stand
era un misterio hasta ahora.
On ne comprenait donc pas
comment il en avait obtenu un.
Come abbia fatto ad acquisire uno Stand
è sempre stato un mistero.
A maneira como ele obteve 
seu Stand é um mistério.