Sentence 1: Officer Lang answered the call when it came to the station. 
 Sentence 3: An FBI agent told Lang to keep the caller on the phone 
 Sentence 4:  The FBI agent traced the call to a cell phone 3 miles away 
 Sentence 5:  But the phone was a prepay, they couldn't identify the caller 
 Option 1: The caller said a bomb was planted in the police station. 
 Option 2: Someone was calling for help.