chisel

That's a good question. I don't think Clark has it because they would have likely shown us him picking it up. I'm not sure how Lex would have known about it, but I'd say he's still a top suspect. That security guard who is obsessed with Lana could have also taken it. It will be interesting to find out. My bet is on Lex.

I also think Clark got the chisel. He saw the pictures the paparazzi took of her in his barn...he and Chloe knew she had it, don't think Lex knew.