The detectives 'dug into' his past and learned that he had once lived in another country.
Her fingernails 'dug into' my hand. = She 'dug' her fingernails 'into' my hand.
The salesman 'dug in his heels' and refused to lower the price any further.
(..) Bones, I'm sorry. What are they going to do with his remains? Can I do that? You sure? Yeah. You dug it. So did Sweets help you with Parker? I told Parker that it's... best just to walk away sometimes. What, sometimes? Isn't it always better to walk away? (..)2008 TvShow: Bones Title: The Finger in the Nest Season: 4 Episode 3