STOCKHOLM (AFP) A Pakistani airliner made an emergency landing in Stockholm over a bomb threat Saturday, but hours later Swedish authorities released a detained suspect after no explosives were found. The Pakistan International Airlines (PIA) Boeing 777 was on its way from Toronto to Karachi when it diverted to land at Arlanda airport around 0730 GMT, following an anonymous phone call warning a man on board may have explosives, police said. After questioning the suspect, a Canadian citizen of Pakistani origin, and thoroughly searching the plane but finding no explosives, he was released without charge and allowed to leave Sweden. The prosecutor on duty decided not to keep the man suspected of having explosives on the airplane in detention, Swedish prosecutors said in a statement. The suspicions against this man are not sufficiently solid to keep him in detention and so he is free to leave Sweden, the statement said, adding that no further information can be given for moment. Canadian authorities said they were opening an investigation into the alert, which was triggered by an anonymous phone call from a woman in Canada. After being alerted to the possible presence of a bomber on board, the crew of PIA flight PK-782 decided to make the emergency landing in Sweden. A woman contacted the Canadian police and said there was a man on board that could have explosives on him. We do not know for the moment who this woman is, Janne Hedlund of the Stockholm police told the TT news agency. Hedlund said the call came from a telephone box. The plane was carrying 261 passengers, including Canadians, Pakistanis and the suspect, and 18 crewmembers, according to PIA. It was taken to an isolated area of the airport where police used sniffer dogs to search it and the baggage for explosives. The searches were finished in the afternoon, we didnt find anything suspect or dangerous, said Stockholm police spokesman Kjell Lindgren. The passengers were led inside the terminal and received food and assistance, an airport spokesman said, adding that psychological counselling was on hand. Police interviewed some of the passengers in addition to questioning the suspect, who was held at the airports police station. Swedish police said the man was a Canadian citizen aged around 30, while a PIA spokesman said he was of Pakistani origin. After receiving the all clear from Swedish authorities, the plane took off around 1500 GMT for Manchester in northwest England. The airline decided to send the plane on to Manchester because the crew was too tired to complete the flight to Pakistan, Arlanda airport spokesman Jan Lindqvist said. Citing the police, PIA spokesman Syed Sultan Hassan said the suspect passenger was of Pakistani origin.