Yes. The accused in this case is singular, but if there were multiple accused then if you had used 'were' then it would be okay. In reference to an incident where people were injured, 'the injured' can work, and would be plural, can't think of any way you'd use it as a singular reference even if only one person was injured, in that case you'd use 'the victim', or 'the injured man/woman'. This kind of language is really common in news reports and fantasy/fiction stories but not very colloquial, it can sometimes be used in conversation when generally describing events, but we'd stick with the ones that describe more categories of people, like 'the rich', or 'the poor'. It gives a very specific tone, like saying 'The banished...' instead of 'The people banished from...' or 'The banished people...' sounds more like high fantasy. Saying the verb version can also give you this tone, so saying 'The impoverished...' instead of 'The poor...' has this effect as well (Though 'the impoverished' is not great, 'the impoverished people' sounds better to me', or if you want to say that they are generally not in good standing and not just financially you could say 'the downtrodden'). I guess some more other examples, 'The corrupt' (This would be used in story telling or rallying speech), 'The victorious', 'The defeated', 'The sullied' (Definite fantasy thing), 'The impure' (Fantasy), 'The righteous' (Would normally be used as 'the righteous people' but this is also sometimes used in stories). Those are all the examples I can think of right now.