A Pennsylvania woman, Colleen LaRose, already faces charges she pushed the plot in Internet conversations, sometimes using the screen name 'Jihad Jane.'
Paulin-Ramirez, 31, was never formally charged in Ireland. The officials spoke on condition of anonymity because they were not authorized to discuss the case.
Paulin-Ramirez left Leadville, Colo., on Sept. 11, 2009, with her 6-year-old son and told her family she had married a fourth time, to an Algerian she had met online, her mother said.
The charges against LaRose were made public after Irish authorities detained Paulin-Ramirez, her Algerian husband and five others. Those suspects are linked to LaRose, a U.S. official previously told The Associated Press. That official was not authorized to discuss the case and spoke on condition of anonymity.
When the charges were unsealed last month against LaRose, 46, it marked one of only a handful of times the U.S. has filed terrorism charges against a woman.
LaRose has pleaded not guilty in the case.
In a four-count indictment filed in Philadelphia, authorities say she conspired with others overseas and pledged to commit murder in the name of a Muslim holy war, or jihad.
LaRose apparently spent long hours online in recent years while caring for her boyfriend's elderly father in a small eastern Pennsylvania town. The congressman who represents the district said she had cooperated with authorities after her arrest last fall, which went unannounced until seven suspects were detained in Ireland in March.