why do journalists and authors often put brackets around words in seemingly strange parts of sentences?

Question

For example, a sentence I just read went as follows:

> “‘I don’t think [the book] had anything to do with his arrest and neither does Anne Marie Schubert,’ he says.”—(Excerpt from the appendix of ‘I’ll Be Gone in the Dark’ by Michelle McNamara)

Found in Other.

Answer 1

the words in the brackets have been added or altered by the author not the person/ have not been said by the person quoted