So something that I've gathered from briefly scanning over the twitter posts is that Bruce Klugman eludes to having some information on Lennie that Lennie would want to keep under wraps. In the dialog between them Klugman mentions wanting to do something about the vacant lot next to guttman's. When Lennie responds that he wouldn't have interest in that Klugman post a hidden threat when he says "don't mess with me, I've been digging up more than foundations lately." It appears that these things that klugman "know" he will try and use against Lennie to get his cooperation.
It may also be important to note the post by Lennie where he mentions a mop being needed on lane 17.
Also, remember to follow @thegintercode on twitter. There was a post made from this account earlier that said "Poor Lennie Guttman has just four days to live, I wish a warning I could give."