The Indianapolis-based device maker has been the focus of attention since reports earlier this year that it failed to inform regulators about problems with its popular Ventak Prizm and Contak Renewal implants. This week, the company announced it is the subject of a Department of Justice probe into the circumstances surrounding its recall of both models. Over the past month, the safety issue has threatened to become a spanner in the works for Guidant's scheduled merger with medical products giant Johnson & Johnson.