Amazon has The Missing Element by John L. Betcher
After decades of clandestine government operations, James “Beck” Becker and his wife Elizabeth return to Beck’s childhood home town to enjoy a settled retirement in the small Mississippi river community of Red Wing, Minnesota. But “settled” is a relative term and no matter where Beck goes, intrigue follows.
When Minneapolis computer genius, Katherine Whitson, disappears under peculiar circumstances, her husband exploits a sympathetic Red Wing acquaintance to enlist Beck’s aid in finding her.
As Beck searches for Katherine, the tangled trail leads from her luxury Minneapolis Warehouse District condo, through her husband’s extra-marital escapades, past the entrenched hierarchy of elite computer professionals, and into the mind-bending world inside computer microprocessors.
Katherine’s kidnapping is clearly more complicated than a typical abduction.
As it turns out, the Beckers must use all of their considerable experience — his as a military intelligence operative; hers as a CIA code-cracker — to save Katherine and bring her abductors to justice.