in what way is it made clear that the new guest of the admiral benbow inn was an unusual man? how is it suggested that he may have been a pirate? when do we know this definitely

One day, an old, brown, dirty, ragged seamen with a sabre cut on his cheek, arrives at the inn and satisfied that the inn contains few people, throws down some gold money and stays for several months. Calling himself a Captain, he often sings (especially when drunk) a pirate-like song. During the day, he spends his time near the cove or the cliff, looking for something or someone through his telescope. Without fail, he always inquires if any new seaman has appeared and if they had, he kept a low profile. He hires Jim to alert him about any strange seamen that should come by. All this indicates the stranger is or has something to do with pirates.