Criminal Sentence 246: Buried in Bad Grammar

From a book about an ancient pot that was smuggled out of Italy and then broken:

"Buried in documents from his legal files, I found another reference to the 15 fragments."

The question here is "What is buried in his legal files?" Is it "I" or perhaps the reference? Unless the "I" of this sentence is chest deep in paperwork, I believe it's the reference that is buried.

Don't steal ancient pottery, and don't write misplaced modifiers!