For years, Naseema Sami exhibited strange behavior, her family said.

She believed that someone was watching her, that “the trees bow to her," and that she was being illegally tracked through a device implanted in her tooth, according to court filings in Montgomery County.

Those delusions peaked in March, when Sami killed two women after breaking into a home in West Norriton Township, a community that hadn’t seen a murder in decades. Now, Sami’s defense attorney, Carrie Allman, is using her client’s paranoia and mental health issues to craft an insanity defense in her murder trial, set to begin Dec. 3.

“This is not a question of who did what,” Allman said at a hearing Friday. “It’s really a question of why this occurred.”

Sami, 44, is charged with two counts each of first- and third-degree murder, as well as criminal trespass, endangering the welfare of a child, and related offenses. Prosecutors, led by Deputy District Attorney Thomas McGoldrick, have said they will not seek the death penalty in the case.

Sami confessed to the attacks, saying she lashed out in self-defense because one of the victims, Diane Frost, 78, was “pushing buttons in her head,” according to court documents. The Folsom resident had rented a room 20 years earlier in Frost’s home, and drove to the house March 7 with her 6-year-old son, police said.

She did so, she told investigators, after suddenly feeling as if she was in danger.

When she arrived at Frost’s home, she entered through an unlocked door and was soon confronted by a neighbor, Lorraine Gigliello, who asked why she was there, police said. Sami began hitting Gigliello, 68, in the face and chest, according to the affidavit of probable cause for her arrest.

Sami broke a bottle of tomato sauce and began slashing at Gigliello with a shard of broken glass. Frost came home during the fight, and Sami pushed her into the bathroom, knocking her into the tub. There, she kicked “her in the head and neck until she died,” Sami told police.

Sami and her son remained in the home for three days, when officers performing a wellness check found the two hiding under a bed. She told investigators they remained “because it was not safe to leave" and that “God had already forgiven her,” according to court filings.

Her son witnessed the slayings and provided a statement to staff at Mission Kids, the county’s child-welfare center. Though the boy will not take the stand against his mother, his recorded statement will be played for the jury in the trial, according to McGoldrick.