A Michigan woman has been convicted of murdering her son, dismembering his body with a power saw and then scattering pieces of it across the countryside.

A Macomb County jury of eight women and four men deliberated for only one hour and 40 minutes Monday before convicting Donna Scrivo, 61, of premeditated murder and other charges in the January 2014 death of her son, the Detroit Free Press. The jury rejected her story that she had been handcuffed, gagged with a scarf and held hostage while a masked intruder killed her son, Ramsay Scrivo, and then cut up his body in the bathtub of his St. Clair Shores condo.

She will be sentenced to a mandatory term of life in prison without parole on June 23 in Macomb County Circuit Court. The jury also convicted her of disinterment and mutilation of a body, and removing a body without the permission of the medical examiner. Scrivo testified she was held hostage for five days by the intruder, who forced her to help dismember and dispose of her son's body across rural St. Clair county. She remained silent, she said, because she was afraid the intruder would kill her other son, nieces and other relatives.

Ramsay Scrivo was drugged, killed by ligature strangulation and dumped in a bathtub, prosecutors said. A registered nurse, Scrivo admitted under oath that she's not perfect.

"I'm not mother of the year. I have multiple problems," Scrivo testified. "I think I did everything to protect the rest of my family. I did everything he told me to."

The motive for the crime is unclear. In 2013, Scrivo sought guardianship and hospitalization of her son, who reportedly had been diagnosed with psychosis and had threatened suicide after the death of his father, according to earlier coverage.

According to court documents at the time of her arraignment, Scrivo had been captured by in-store video buyng a circular saw that police said was used to dismember her son's body. She admitted during the trial that she bought the saw, but said it was for a household project.