An American grandmother has spoken of her fears for her 6-year-old grandson who has been placed in foster care in Ireland following the arrest of his mother in the "Jihad Jane" plot.

Christine Mott says her daughter Jamie Paulin-Ramirez, 31, took her 6-year-old son with her when she abruptly left for Ireland in the fall.

Mott says her daughter then married an Algerian who she met online.

Mott says Paulin-Ramirez was a straight-A nursing student before this happened.

"This is about my baby," Mott told AP. "We need some help to get this baby back. I'm concerned about my daughter but I'm concerned about our baby boy because he shouldn't be caught in the middle of this."

The Motts said their daughter's conversion was a complete shock.

They said she announced last spring that she was becoming a Muslim and began wearing headscarves and a hijab.

"It came out of left field," Mott said. "I knew she was talking to these people online... What caused her to turn her back on her country, on her family and become this person? I don't know how or why. All I know is she was in contact with this Jihad Jane.

"The only thing I could think of is that they brainwashed her."

Irish police have not released the names of the seven Muslims they arrested in Ireland only saying they were three Algerians, a Libyan, a Palestinian, a Croatian and an American woman married to one of the Algerians.

The seven were arrested Tuesday, as U.S. authorities unsealed a terror indictment against the so-called Jihad Jane, 46-year-old Colleen LaRose of Philadelphia.