An unknown group may claim responsibility.Logical formLearned from428 sentences. A date can be unknown.Logical formLearned from375 sentences. Reasons can be unknown.Logical formLearned from372 sentences. A cause of death can be unknown.Logical formLearned from362 sentences. A name can be unknown.Logical formLearned from361 sentences. A cause of a crash can be unknown.Logical formLearned from357 sentences. A female can be unknown.Logical formLearned from356 sentences. A number can be unknown.Logical formLearned from355 sentences. A cause of a fire can be unknown.Logical formLearned from353 sentences. A status can be unknown.Logical formLearned from340 sentences. A fate may remain unknown.Logical formLearned from326 sentences. An origin can be unknown.Logical formLearned from320 sentences. Persons can be unknown.Logical formLearned from315 sentences. An identity can be unknown.Logical formLearned from288 sentences. A cause of an accident can be unknown.Logical formLearned from270 sentences.