Need help finding an Edgar Allan Poe book

I'm looking for the title of a book I read when I was a kid. I remember the words: "The Poe" on the book cover but can't remember the title of the book. The book is told through the eyes of a young man. He and his sister are extremely poor and thin, and the plot revolves around the young man trying to solve the mystery of his mother's death. Some features of the story I can recall are that there was a portrait of some importance and this memorable scene where the man looked across a window in an apartment at his sister. Please help if you can! Thanks