PLYMOUTH, Mass. (AP) — A Massachusetts woman was indicted by a county grand jury Friday in the killing of her three children in what prosecutors have described as a planned assault while her husband was out.

Lindsay Clancy, 32, is charged with murder and strangulation. She is is currently held without bail and is being treated in a medical facility. Clancy had been arraigned in Plymouth District Court in February. A not guilty plea was entered on her behalf in that court hearing.

A lawyer for Clancy, defense attorney Kevin Reddington, said at the earlier hearing that Clancy may have been suffering from post-partum psychosis — something the prosecution rejected.

An email and phone call to Reddington seeking additional comment were sent.

Investigators said that on Jan. 24, Duxbury Police were called to her home and three children - ages 5, 3 and 8 months - were found in the basement. Two had been dead and one died several days later.

The state medical examiner ruled that the causes of death were asphyxia or complications from asphyxia.

The labor and delivery nurse is scheduled to be arraigned on the charges in Plymouth Superior Court at a later date.