Desiree Young, the mother of the boy, filed the lawsuit last month, asking Multnomah County Circuit Judge Henry Kantor to compel Terri Horman to reveal the whereabouts of Kyron Horman, 10. The suit also seeks $10 million in damages, The (Portland) Oregonian reported Wednesday.
Kyron disappeared June 4, 2010, after Terri Horman said she dropped him off at his school. He never made it to his classroom, though police have not named her as a suspect or person of interest.
Attorney Peter Bunch filed a motion with the court saying the ongoing criminal investigation into Kyron's disappearance would interfere with the civil case because of an overlap of evidence.
"Young wants no further delay in resolving the disappearance of her son. While one can sympathize with Young, her lawsuit is, at its core, an attempt to circumvent established procedures for discovery in criminal proceedings and is an attack on Horman's fundamental constitutional rights," Bunch wrote.
Bunch used the same argument to delay Terri Horman's divorce proceedings from Kaine Horman for two years. The divorce is scheduled to proceed in October, The Oregonian reported.