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.
(..) (crowd laughs) - (farts) - Ahh! Oh, murdered by a boar. The great big hairy whore. He dug in his tusks and dug out my guts and soon I am no more. Oh, come, Father, in bed you must lie. I love you, Father. (..)2016 TvShow: Game of Thrones Title: The Door Season: 6 Episode 5