Gaza Strip - A Hamas leader assassinated during a visit to Dubai last month exposed himself to attack when he breached security protocol by talking about his trip over the phone and making hotel reservations on the Internet, the Islamic group said Saturday. The methodical stalking and killing of Mahmoud al-Mabhouh in a luxury hotel room, widely blamed on Israel's Mossad spy agency, has put Hamas on the defensive over purported security lapses. The new details emerged as the case has spread across several continents with investigators probing possible credit card links to US-based banks and European officials grilling Israeli envoys over fraudulent passports. Hamas legislator Salah Bardawil said al-Mabhouh unwittingly led his attackers to him by openly planning his travels, a move that would make him easily traceable if he were already under surveillance. "Al-Mabhouh called his family by phone before he traveled to Dubai and told them of his plan to stay in a specific hotel, and he booked his travel through the Internet. This undoubtedly created a security breach in the movements of al-Mabhouh," Bardawil told reporters in Gaza. Al-Mabhouh's brother, Fayek, denied the phone leak, saying the slain operative didn't reveal any details regarding his reservations or other travel plans.