EVERETT — Prosecutors have filed new charges against a man accused of recklessly neglecting his 81-year-old mother.

Kenneth Strandt, 53, is facing trial this fall on a count of first-degree manslaughter. Prosecutors are alleging aggravated circumstances based on the victim’s vulnerability.

Irene Strandt died in December. An autopsy found that her son’s “act of restraining her directly contributed to her death,” leading to a ruling of homicide.

The initial charges said that Kenneth Strandt failed to call for help as his mother languished on the floor for days with a broken hip, failing kidneys and other health problems.

Her legs were bound at the ankles with a tied and knotted purple sweater. The bindings left marks on her legs from cutting off the circulation, according to the charges.

She was taken from her home east of Mill Creek to the hospital. Kenneth Strandt was arrested and booked for investigation of first-degree criminal mistreatment, a felony.

His mother later succumbed to her injuries.

In January, a judge ordered an evaluation to determine whether Kenneth Strandt was competent to assist in his own defense. His attorneys said they were concerned that an undiagnosed developmental disability was affecting his ability to communicate about the case.

He was found competent in March and released from jail in April pending trial. His only criminal history is a DUI from 1986.

The new charges from July cite the autopsy findings regarding his role in the death.

Medical records show that Irene Strandt had advanced dementia, and her son had been informed that she required around-the-clock care, according to court papers. Police also were told that Kenneth Strandt was her only surviving child.

Rikki King: 425-339-3449; rking@heraldnet.com. Twitter: @rikkiking.