Book with a character that repeated the phrase, i venture to say. [s]

[Maggie]

I read this book about five years ago but all I remember is it follows a young teen , I think hes in high school, who befriends a nerdy kid Who says, "I would venture to say" all the time. I think the main character use to search for arrow heads in a field when he was younger.
At some point in the book, i think his friend is thought to have been killed or died somehow, but at the end of the book, the main character receives a letter from an anonymous person where the phrase, "I venture to say" is repeated multiple time alluding that his friend is still very much alive.
That's all I really remember. Sorry I don't have more. I Know I really liked this book and would love to read it again. I would appreciate any help and feel free to ask questions.

[Tab]

Was this a fantasy, mystery, etc?
Anything about the cover?

[Maggie]

I think it was mystery. I know its extremely vague but I cant remember the cover or anything else.

[Juels]

Maybe The Body of Christopher Creed by Carol Plum-Ucci?

[Maggie]

Yes Juels,that is it. I've seen that title name before, it's a popular book isn't it? cant believe i forgot nearly everything but anyway THANK YOU! THANK YOU!I will be checking it out today. :)

[Juels]

You're welcome. You provided good details that helped the search.