Definition: In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.
Input: Marcus Conway:  Detective , I would think very carefully before making these kinds of accusations .
Kate Beckett: Mr. Conway , I am not making any accusations . I am simply stating fact . We have a witness that heard you threatening Ella Hayes , and another _ one _ that saw you near where she was killed .
Richard Castle: Right about the same time she ended up that way .
Kate Beckett: You need to explain yourself .

witness