If I use the word "accused" as a noun, representing multiple people who are accused, what would the possessive form be? As in "the accused lives"?
Let's work this through step by step:
First let's say that Bob is thought to be an arsonist - he is accused of setting fires. We have Bob as the noun (proper noun at that) and Bob's matches are part of the evidence. So far so good with first person singular.
And then we go to the newspaper and see that the reporter has called Bob "the accused" and it talks about "the accused's matches". And that gets us through third person singular.
So let's now change it up and get to the question - a group of people are setting fires. First off, can we use "the accused" as a pronoun for a group? Yes we can.
So since we can use "the accused" as a pronoun, we can find a possessive form. And in particular, let's look for the possessive form of the lives of the accused.
How do we handle this? Let's try out a couple of things and see what happens:
We've already handled it one way - by shifting to a longer form - ex. The accused were sentenced today. The lives of the accused will change forever.
Can we say it this way - The accused were sentenced today. The accused's lives will change forever.
It's a little awkward and the second sentence only works if it's established that "the accused" refers to multiple people (like was done in the first sentence of those examples), but it does work.
And so I disagree with the answers in the yahoo answer website (except for the bottom ranked one which agrees with me) where this exact question was posed 7 years ago.