Definition: In this task, you need to generate an appropriate title for the given summary of some paragraph. The generated title must be short and should include the main topic of the given text. Your summary should be less than 20 words long.
Input: Five aid workers abducted last month in north-east Nigeria's Borno State have been killed, reportedly by jihadists.

Nigeria's Boko Haram crisis: Aid workers 'killed' in Borno state