Questions over the role of a New Jersey matrimonial firm in an international child abduction are at the heart of an unusual suit set to go to trial in Bergen County, N.J., this summer.

Madeline Marzano-Lesnevich and her firm, Lesnevich & Marzano-Lesnevich of Hackensack, N.J., are accused of helping former client Maria Jose Carrascosa take her daughter to Carrascosa’s native Spain, in violation of a parenting agreement with the child’s father, Peter Innes.