WASHINGTON — Their mother is considered incompetent to stand trial, and what happened to Sarah and Jacob Hoggle remains a mystery, but family members have a new tool to try to find the children — age-progression images.

The National Center for Missing and Exploited Children provided the images of the Gaithersburg, Maryland, children, who were 3 and 2 years old when they disappeared in September 2014.

“We realize that some feel the pictures have overly aged the children,” said a Facebook post on the FindSarahFindJacob page. “However we are thankful to the National Center for Missing and Exploited Children for their hard work and appreciate any and all help we can get at this time.”

The children’s mother, Catherine Hoggle, is in treatment in a state-run mental health hospital. She has repeatedly been found by mental health professionals not competent to stand trial.

Hoggle was charged in 2014 with neglect, abduction and hindering — all misdemeanors. She initially gave different stories of where her children are, eventually saying they were left with an old friend.

Earlier this month, the children’s father, Troy Turner, told reporters he’d been informed by Montgomery County prosecutors they have enough evidence to indict Hoggle on murder charges.

A spokesman for State’s Attorney John McCarthy would not discuss whether prosecutors believed they had enough evidence, although McCarthy has said previously they were building a case.

WTOP’s Neal Augenstein contributed to this report.