Three relatives of a man named as a person of interest in the 1975 slayings of two Maryland sisters will be arraigned in Virginia on charges that they have impeded the investigation.

Leslie Engleking is charged with perjury. Gladys Stangee and Amy Welch-Johnson are charged with obstruction of justice. Their arraignments are set for Thursday in Bedford County General District Court.

All three are relatives of Richard Welch, who has been named as a person of interest in the deaths of 12-year-old Sheila Lyon and 10-year-old Catherine Lyon of Wheaton, Maryland. Welch hasn't been charged and has said he's innocent. His nephew, Lloyd Lee Michael Welch Jr., has been charged with two counts of murder.

Authorities say the sisters were kidnapped and taken to Bedford County, where they were killed.