Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of industrial products company Trinity Industries Inc (NYSE:TRN) dropped as much as 10% today after it became the target of a criminal probe.

So what: The U.S. Department of Justice is investigating the role of Trinity's guardrail systems in at least eight deaths, and that could be just the tip of the iceberg. Bloomberg is reporting that federal investigators are interviewing potential witnesses about the company's relationship with the Federal Highway Administration and the involvement that could have had on a grand jury investigation.  

Now what: Just when the company thought its legal troubles were over this criminal investigation popped up. Management did say that they haven't been contacted by the DOJ yet, and right now it's just speculation as to where the investigation will lead. For investors, it's risky buying into a company with legal trouble like this because it's completely unknown if the investigation will result in major damages or blow over entirely. I would steer clear of shares given the uncertainty, but keep an eye on what does (or doesn't) come of this in the future.