Walter Primrose and his wife Gwynn Morrison, who are in their 60s, were accused of stealing the identities of Bobby Edward Fort, an infant boy who died in 1967, and Julie Lyn Montague, a baby girl who died in 1968, according to a complaint filed last week in Hawaii federal court.

Since 1987, the couple used the identities of the children, who were from Texas, to obtain driver's licenses, Social Security numbers and passports, the complaint said.

Primrose also used Fort's identity to enlist in the U.S. Coast Guard in 1994, U.S. prosecutors said in the complaint. He used it until he retired and began working as a Department of Defense contractor in 2016.

In a motion filed ahead of a detention hearing scheduled for Thursday, prosecutors said Primrose had secret security clearance throughout his time as an avionics electrical technician with the Coast Guard and as a contractor.

The court documents did not offer a possible motive for the alleged identity theft. Prosecutors argued the couple should be held without bail, citing Primrose's ability to use his electronics expertise for surreptitious communication.

An attorney for Primrose declined to comment. An attorney for Morrison was not immediately available for comment. Primrose and Morrison have been in custody since their arrest on Friday.

While working for the Coast Guard under the false identity, Primrose failed to report several trips to Canada as required under his secret clearance status, although he did report other foreign travel, the detention motion said.

Morrison lived in Romania when it was within the Communist bloc, and federal agents seized photographs of the pair apparently wearing uniforms of the KGB, the former Soviet Committee for State Security, the motion said.