Police 
     pursue 
         potential 
             political 
                 provocateurs.

Alliteration is when two or more words that start with the same sound are used repeatedly in a phrase or a sentence. The repeated sound creates the alliteration, not the same letter. For example, ‘tasty tacos’ is considered an alliteration, but ‘thirty typist’ is not, because ‘th’ and ‘ty’ don’t sound the same.