Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: Dhaka, Bangladesh (CNN) -- Gunmen shot and killed a Saudi diplomat in Dhaka, Bangladesh's capital, on Tuesday, police said. Bangladesh police said Khalaf Al Ali, 45, had served two years at the Royal Embassy of Saudi Arabia in Dhaka as head of citizens' affairs. The Saudi Embassy in Dhaka confirmed the death but declined to make a comment. Ali was shot dead in the city's highly secured Gulshan diplomatic zone in front of his rented apartment at about 1 a.m. Tuesday, and he died at a local hospital about 5 p.m., authorities said. Lutful Kabir, a deputy commissioner of Dhaka's metropolitan police, said no motive for the killing has been found.Authorities say Khalaf Al Ali, 45, was shot about 1 a.m. Tuesday and died about 5 p.m.Crime occurred in Dhaka's highly secured Gulshan diplomatic zone at Ali's rented apartmentGuard at the home said Ali went for his usual walk and was attacked when he returnedDhaka metropolitan police say no motive has been found 
 Question:... We'll use all possible means to bring the culprits to book," _ Foreign Minister Dipu Moni said.

Bangladesh