This is the lightest penalty recommended under state sentencing guidelines, according to documents filed on Thursday.

Mohamed Noor was initially convicted of third-degree murder and manslaughter in the 2017 death of Justine Ruszczyk Damond, a dual US-Australian citizen. He was sentenced to 12-and-a-hald years on the murder count, but last month, the Supreme Court tossed out Noor's murder conviction and sentence, saying the third-degree murder statute doesn't fit the facts of the case.

Noor is still convicted of second-degree manslaughter and will be sentenced on that count on October 21. Sentencing guidelines call for a range of anywhere from 41 to 57 months, with the presumptive sentence being four years.

Noor was taken into custody on April 30, 2019, and has already served more than 29 months. In Minnesota, defendants with good behaviour typically serve two-thirds of their sentence in prison, and the rest on supervised release. If Noor receives the presumptive four years for manslaughter, he could be eligible for supervised release around the end of this year.

If the judge agrees with the defence and sentences Noor to 41 months, his release could be imminent.

Prosecutors haven't said what sentence they will seek.

Noor's lawyers argue that a 41-month-sentence recognises the "particularly harsh" nature of Noor's incarceration, as well as the good behaviour he has shown in prison.

Lawyers Tom Plunkett and Peter Wold wrote that by the time Noor is sentenced, he will have served 110 days in administrative segregation in Minnesota's only maximum security prison. While in segregation, he spends 23 hours a day alone in a two-by-three metre concrete room and is not allowed visitors, they said.

He is allowed one hour of recreation for three to four days a week and a 10- to 20-minute phone call, and then spends the rest of his recreational time walking in a circle, they wrote.

"He never steps into the light of day," the lawyers wrote, adding: "Many days he has no human contact beyond the scrape of a food tray making its way into his cell."

Noor spent the bulk of his incarceration in an out-of-state facility. While there, the COVID-19 pandemic created harsh conditions, his lawyers wrote, saying a lockdown stopped all religious services and has prevented family visits for more than a year.

The lawyers said that while he has been in custody, he has received 19 positive behaviour reports. The reports, included in Thursday's court filings, commend Noor for his willingness to help others, his hard work as a janitor and his positive attitude and interactions with others.

In September of 2020, Noor was recognised with a September 11th Worker Award, in honour of those who died on September 11, 2001. A sergeant who recognised him wrote that he was committed to the job and respectful of others and, "It is my hope that you will continue to inspire others to achieve their goals, far beyond these walls".

Noor testified in his 2019 trial that a loud bang on his squad car made him fear for his and his partner's life, so he reached across his partner from the passenger seat and fired through the driver's window.

His lawyers have said he believed he was saving his partner's life.

Australian Associated Press