Oslo, Norway (CNN) The man suspected of opening fire at a mosque near the Norwegian capital of Oslo on Saturday has expressed right-wing sympathies online, the police said in a news conference Sunday.

Superintendent Rune Skjold told reporters the suspect, described only as a Norwegian man in his 20s, has praised figures like Vidkun Quisling, the leader of Norway under Nazi occupation during World War II.

The shooting is being investigated as a "possible act of terrorism," police said.

The man has been charged with the murder of a woman found dead in his home and is also facing an attempted murder charge in the shooting at Al-Noor Islamic Center in Baerum, a district just west of Oslo. One person was injured in the incident, sustaining minor injuries, police said.

Shortly after the attack, investigators found the body of a young woman at the suspect's home in Baerum. Police said the victim is the 17-year-old stepsister of the suspect.

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