For security reasons the four day trial is to be held in one of two high security court rooms at Stockholm District Court.
More than ten witnesses have been lined up to testify at the trial, four of whom are former colleagues of the victim.
According to prosecutor Pär Andersson, there is compelling evidence to suggest that the 55-year-old defendant is guilty as charged.
“There is technical as well as oral evidence,” he said.
The 55-year-old suspect is due to testify after lunch on Thursday. When taken in for initially questioning he said that he had acted in self defence. He later refused to answer any questions regarding his alleged involvement in the murder.
Fredrik Widén, who was 32, was shot as he attempted to detain the suspect in central Nyköping, 100 kilometres south of Stockholm. Police were enforcing an order from mental health authorities to section the 55-year-old man.
Over the last 100 years, 30 Swedish police officers have been killed in the line of duty.