The Palestinian ambassador to Prague was killed in an explosion that was triggered when he opened the door to a safe, Czech police said.
"According to information from the investigation so far, this was definitely not a terrorist attack," national police president Martin Cervicek said on Czech Television.
Police spokeswoman Andrea Zoulova said an explosive - which may have been part of a security mechanism - went off after the safe was opened. "With the greatest probability, an explosive device placed on the door of the safe was triggered," she said.
The Palestinian foreign ministry, in a statement reported by the official WAFA news agency, said the blast happened minutes after Jamal opened a safe that had come from the embassy's old offices.
Some safes can be fitted with small charges to destroy secret documents in the event of the lock being tampered with.
More top news
The video, obtained by ITV News, shows scores of migrants desperately trying to board lorries in a restricted area within the tunnel.
Ex-Spitfire pilot Allan Scott, 94, said he was told off by the Queen when he first met her in 1943 when she was just 16.
Last minute preparations are going on at the Church of St Mary Magdalene where Princess Charlotte will be christened.