Dawn Signed News Today : Breaking News, Live Updates & Top Stories | Vimarsana

>> reporter: and so dawn oxley was offered a limited immunity agreement, cooperate with the prosecution, testify truthfully against james and you won't be prosecuted. a sort of get-out-of-jail-free card. why make that deal with her so soon? you had her statement. why not hold off for a while and be patient and then get them both? >> let's say we don't do the deal with her and we go out and arrest him. what's our evidence? >> reporter: dawn signed the agreement and james was charged with first-degree murder. but the end of the story, oh, no, not even close. the truth had been hiding, but it was...

That sometimes you need the help of one of the people involved to get the main person. >> reporter: and so dawn oxley was offered a limited immunity agreement, cooperate with the prosecution, testify truthfully against james and you won't be prosecuted. a sort of get-out-of-jail-free card. why make that deal with her so soon? you had her statement. why not hold off for a while and be patient and then get them both? >> let's say we don't do the deal with her and we go out and arrest him. what's our evidence? >> reporter: dawn signed the agreement and james was charged with first-degree murder. ...