The first person to question the "Burke was asleep" story was Ramsey friend Barbara Fernie. She and her husband John knew the Ramseys very well, and they were the 2nd phone call PR made that morning to come to the house. Barbara knew Burke to be an early riser, he typically got up around 5:30AM. IIRC, PR confirms this in one of the police interviews. Barbara was suspicious that the Ramseys were saying Burke was asleep the whole time. PR's story was that she screamed, JR confirms this and that he heard the scream from their bedroom on the 3rd floor. BR's bedroom was on the 2nd floor. Barbara did not believe that early riser Burke would not have heard the scream from the 2nd floor.
Later, BR recounts PR bursting into his room, flipping the lights on looking around and saying, "oh my God, oh my God". He describes hearing her "going psycho" downstairs. He describes JR as being calm and trying to calm PR down and discussing calling the police. He recalls JR going into his room, turning the lights on and looking around. He was awake.
The 911 dispatcher (Kimberly Archuleta) heard voices on the line after PR had thought she hung up the phone. The line had not disconnected. She informed her supervisor that she had heard something and wondered if the police were aware, which they were not. So they started investigating. They at first sent the recording to both the FBI and the SS, however neither agency had the latest technology at that time in order to successfully enhance the recording. Police then contacted the Aerospace Company in California for assistance. It was determined that the original recording was an older, low-fi technology, it was recorded on dictaphone. At that time dictaphone recordings were used for capturing speech for transcription, but the overall sound quality was not very good. So the original recording first had to be transferred to another format that offered a superior quality of sound with more options to enhance audio nuances and reduce noise to obtain a more clear end product. This involved digitizing the original recording and other techniques that were available at the time that Aerospace was using in their labs. They had the latest technology to apply to ensure maintaining the integrity of the original recording in order to enhance.
They were successful in enhancing the recording so that three voices could be heard. 2 adults, 1 child. This recording has been held close to the vest by police in order to protect the integrity of the recording. All of the recordings that have surfaced on the internet have been enhanced with well known audio techniques, but they do not have the advantage of utilizing the original recording and transferring to another digital format. Audio engineers who have attempted to enhance the recording are not doing so from the original source, which is why so many people have said they can't hear the voices.
The Boulder Camera reported on the enhanced recording and that Burke's voice could be heard. JR and PR later said they did not know BR was awake.