The most common and most likely answer to this crossword clue is the 8 letter word DOPESTER
I've seen this crossword clue in Independent
D
O
P
E
S
T
E
R
Buddy explains!

The straight part
We know that "someone with information in America" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case someone with information in america = dopester.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DOPESTER mean?
DOPESTER noun- An individual who is from a street gang and sells drugs.