More than 5 1/2 years after two Reston brothers went missing, and nearly four years after a kidnapping warrant was issued for their mother, authorities are still trying to track down all three.

Authorities say the father of Alec and Dominic Gardner last saw his sons Dec. 6, 2004.

That's when authorities say their mother, Stefanie Zachariadis Gardner, left Reston with the boys, then ages 3 and 1. A warrant for her arrest on international parental kidnapping charges was issued in U.S. District Court in Alexandria in August 2006.

Zachariadis Gardner and her sons are believed to be in Germany.

A notice that she is wanted in Virginia is listed on Interpol's Web site. An FBI spokeswoman said this week that the kidnapping warrant is still active.

When there are active warrants and notices in missing-persons cases, the alleged kidnapper will be stopped if intercepted by law enforcement officials, said Preston Findlay, a lawyer with the National Center for Missing and Exploited Children.

Family abductions are complicated cases, especially when international authorities are involved, Findlay said.

He said the boys' father filed an application to have the children returned to the United States under the Hague Convention, the treaty that establishes a civil process for returning children wrongfully removed from their country of residence.

But German courts denied the application, Findlay said.

Alec Gardner is now 8 years old, and Dominic Gardner is now 7 years old. Stefanie Zachariadis Gardner, now age 35, is described as 5 feet 6 inches tall and 120 pounds. She has brown hair and brown eyes.

Anyone with information about the case can call the National Center for Missing and Exploited Children at 800-843-5678.