The most common and most likely answer to this crossword clue is the 7 plus 4 letter word CHINESE BURN
I've seen this crossword clue in The Times
C
H
I
N
E
S
E
B
U
R
N
More clues leading to the result CHINESE BURN
Buddy explains!

The straight part
We know that "Evidence of torture" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case evidence of torture = chinese burn.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.