MILWAUKEE, Wis. (WTAQ) - The investigation continues, but Milwaukee County Executive Scott Walker is suggesting a concrete panel that killed a teenager was attached improperly.

Walker says no evidence has been found to single out a cause for last month's fatal accident. The 13-ton slab of concrete fell on Jared Kellner, killing the teenager. Two other people were hurt.

A lawyer for the company that built and installed the panels says it's too early to say the current investigation has reached any conclusions. Joshua Levy represents Advance Cast Stone. He says it's not at all clear that the panel failed.