Mayne Reid 
Headless Horseman, A Strange Tale of Texas [EPUB ebook] 

The story takes place in Texas soon after the War with Mexico. Louise Poindexter, a beautiful newcomer, is courted by two men – the arrogant and vindictive Cassius Calhoun and the dashing but poor mustanger Maurice Gerald. Calhoun plots to eliminate his rival when tragedy strikes: Louise’s brother, the young Henry Poindexter, is murdered. All clues point to Maurice Gerald as the assassin. At the same time, a headless rider is spotted in the environs of the Poindexter plantation.