I was just rewatching the episode and noticed that it looked like Hodgins was run over by a Mini - which I think is a interesting coincidence because he's driving a Mini Cooper in "Two bodies in the lab"

ETA:

I loved the whole convo going on in that scene so, here it goes:
Booth: "Easy - Brennan's cell to mine. Right. The message was for me. We have an understanding, we work together"
Angela: "We all work together. She's my best friend. And Hodgings... Hodgins..."
Cam: "She's right, we should assume the message is from Hodgins, not from Brennan."
Booth: "Why?"
Cam: "Because they are buried alive..."
Angela: "... and Hodgins is all about dirt."
Booth: "Okay, great the message is about dirt. Who is it to?"
Zack: "Angela! Hodgins is all about dirt and Angela."
Angela: "But it's numbers, Zack. It's for you. Hodgins would have written me a line of poetry or something."