Two people in Wisconsin have pleaded guilty to crimes related to providing support for the Islamic State, including a woman who used hacked Facebook accounts to share instructions for building explosives and mixing poison, the authorities said Monday.

Prosecutors said the two cases were unrelated. The woman, Waheba Issa Dais, 46, a permanent legal resident of the United States who was born in Israel, pleaded guilty to attempting to provide material support to the Islamic State, also known as ISIS.

She used a series of hacked Facebook accounts to pledge allegiance to ISIS, recruit new members for the terrorist group, encourage supporters who said they wanted to launch terrorist attacks, and share plans for building explosives, prosecutors said.

“Remember Boston Marathon bombing?” Ms. Dais asked an undercover F.B.I. officer on Facebook, according to a plea deal she signed last month. “It was very easy to make. All it needs is a pressure cooker, shrapnel and explosives. Join my channel and research.”