I feel like that black card facing up could be a Gravedigger... The art has the right shape from what I can see, and its a common so statistics are on our side. I'd put a twenty on it I think.
These are amazing. I can't help but wonder the circumstances of some of the items in the photographs. The shoe for example - did someone carry an extra pair of shoes on their backpack and lose one? Or was it lost mid-trek and the poor soul had to continue the muddy journey shoeless? And the laptop! Perhaps a devious hacker who took a hammer to it to avoid being caught by the 5-0? No one will ever know.
Best guess, someone snatched a unguarded bag of some college kid, male most likely based on the cards in the photo. But the most interesting part of this photo is what is missing. I don't see a HDD or it's components and if you have ever taken one apart you know how much fun can be had. As such who ever tore the laptop apart wanted to keep the data intact.