"It is now case close for our part. All that remains is for the criminal investigation department to complete their report," said Eva Bergström at Arlanda police.
A 28-year-old Canadian man of Pakistani origin was released after police questioning on Saturday evening without charge.
"He is free to go where he wants," Karin Rosander, communications director at the regional public prosecution office, told news agency TT. "According to police, the man will receive help with accommodation for the night and then continue his trip tomorrow."
The man was arrested earlier on Saturday for "planning to sabotage an airplane," police operations director Stefan Rådman told AFP.
However, police in Sweden said no explosives were found in the search.
The plane, a Boeing 777 operated by Pakistan International Airlines, was on its way from Toronto to Karachi, Pakistan when it was forced to make an emergency landing at Arlanda shortly after 7.30am.
The landing was prompted after Canadian police, through the country's air traffic authorities, contacted the pilot in the air and said that there may be a suspicious person on board.
Shortly before 7am local time, the pilot contacted air traffic control at the airport and requested landing rights, saying there was a person suspected of having explosives on board.
Passengers were evacuated from the plane and led inside the terminal two hours after landing, where they received food and assistance.
The airplane left for Manchester at 5pm local time to continue its journey to Karachi because the crew was too tired to complete the flight to Pakistan, Arlanda Airport spokesman Jan Lindqvist said.
Regular air traffic at Arlanda was unaffected by the threat. Terminals remained open as usual and all remaining flights left on schedule.
"We have so much capacity that we can put a plane to the side so that it doesn't affect other traffic," Anders Bredfell, press director at the airport, told TT earlier on Saturday.
Separately, Canadian police said Saturday they were looking into whether the bomb alert was a hoax. Under Canadian law, a "terrorist hoax" is a crime punishable with prison time, a spokesman with the Royal Mounted Police in Toronto, Marc Laporte, told AFP.
"It was a woman who contacted the Canadian police and said there was a man onboard who could have explosives with him. It remains unclear who the woman is," said Hedlund.