van cuylenborg: they were very disturbing, of course.hey were written in a manner to be to be unsettling, which they were because we were all uncertain, as were even the police, whether they were from the murderer or not. narrator: the letters were handwritten with no apparent attempt at concealment. detectives hoped this bizarre cat-and-mouse game might finally lead them to who killed jay and tanya. there was some hope by investigators that maybe this was it. maybe this was the break that they had been waiting for. ♪ narrator: in the weeks after a young canadian couple were found murdered outside of seattle, their families received anonymous letters from someone claiming credit for the crimes. van cuylenborg: the first ones arrived christmas of 1987, and it continued, you know, seemingly every couple of months or so. there'd be either a letter or, like, a father's day card and a mother's day card to the parents -- very cruel. narrator: in a possible break, they were handwritten -- a potential source of evidence. as much as they could do