A Pittsburgh-area man has been ordered to stand trial on charges that he killed and dismembered his mother and stepfather before putting their body parts into plastic bags.

Penn Hills police discovered the remains of 73-year-old Olivia Gilbert and her 76-year-old husband, Lamar, in their garage. Police checked on the couple because the sister of suspect Frederick Harris III hadn't seen their mother and stepfather for a few days.

The 47-year-old suspect was found in a locked bedroom when police burst into the home, where officers also found blood-soaked carpet, and five bloody kitchen knives.

Harris, who has been diagnosed with bipolar disorder, has received various mental health treatments since 2001.

Police linked him to the crimes with surveillance video of him purchasing the new garbage containers in which the bagged remains were found.