 In 2013, a team of cold case investigators with the Montgomery County, Maryland, police made a break in the case.They focused on Lloyd Lee Welch, Jr., then serving a lengthy prison sentence in Delaware for child sexual abuse, the culmination of a long criminal record that had begun a few years after the girls' disappearance with a burglary arrest in their jurisdiction.In September 2017, Welch pleaded guilty to two counts of first-degree murder for the abduction and murder of the two sisters.