Norwegian prosecutors sought a 21-year prison sentence for a right-wing extremist who reportedly opened fire in front of a mosque near Oslo last year.
Philip Manshaus, 22, is on trial for "murder" and "terrorist act".
He is accused of killing his half sister and attempting to shoot at Bareum in August.
"He seems to be dangerous for a very long time," said prosecutor Johan Øverberg on the last day of the trial on Wednesday.
Norway's prosecutor's office also argues that the alleged murder of her 17-year-old half sister, Johanne Zhangjia Ihle-Hansen, was a "planned execution" and had "racist motives".
The requested prison sentence has a minimum detention period of 14 years and can be extended indefinitely if the sentenced person is considered dangerous.
Norwegian courts do not issue life sentences.
Philip Manshaus' defense requested an acquittal, arguing that there are doubts about the accused's criminal liability and that he had "a very paranoid perception of the world".
"If the court finds him irresponsible, he could be sentenced to forced psychiatric care," said defense lawyer Unni Fries.
During the trial, three experts found Manshaus criminally responsible.
On August 10, 2019, a suspect wearing a bulletproof camera and vest and helmet opened fire at the Islamic Center Al-Noor, without causing serious injury, before being subdued by the faithful.
There were only three people inside the mosque preparing for Eid celebrations at the time of the shooting.
Later, the police found the body of her adopted half-sister, of Chinese origin, who had been shot four times in her home.
Prosecutors say Manshaus "wanted to kill as many Muslims as possible" and emphasized that the accused shows no remorse.
Norway's Prime Minister Erna Solberg called it "direct attack on Norwegian Muslims”.
A verdict is expected at the trial next week.