The recording is of a cellphone conversation that Amber Tuccaro received while she was in a vehicle south of Edmonton in August 2010 — the last time she was seen.
Mounties have posted the conversation to a website in the hope that someone will recognize the voice of a man in the vehicle, who police say is a person of interest.
Police warn the content is disturbing. The man assures Tuccaro that the vehicle is headed to Edmonton, but Tuccaro appears increasingly skeptical as the conversation continues.
"You'd better not be taking me anywhere I don't want to go," Tuccaro can be heard telling the man. "I want to go into the city."
"We are, we're going," the man responds.
"We're not going into the city," Tuccaro says again.
The man continues to assure Tuccaro that the roads they are taking are headed to the east side of Edmonton. The recording becomes garbled as the call fades, but the man can be heard saying "gravel" right before the call cuts out.
The recording is posted at www.kare.ca and www.albertamissingpersons.ca.
Tuccaro, who was 20 at the time and was the mother of a 14-month old, hasn't been seen or heard from since.
"Please listen to the man's voice. If you do recognize him, call police," Tuccaro's mother, Vivian Tuccaro, said at the news conference where police released the recording.
"There are no words to describe the pain our family feels since Amber's disappearance. We are not complete without Amber."
As the recording was played for reporters, Tuccaro was overcome with emotion at hearing what's believed to be her daughter's last known words and had to leave the room. Police paused the recording until she was gone.
RCMP say it is unusual for them to release an audio recording in the hopes of identifying someone. But they say it has been done before with success.
Tuccaro lived in Fort McMurray, Alta., and flew to Edmonton International Airport with her son and a female friend on Aug. 17, 2010, police said. She booked into a hotel in Nisku near the airport and spent the day in the community.
The next day, police say Tuccaro left her hotel room to catch a ride into Edmonton and got into an unknown man's vehicle. She was reported missing two days later by her family.
In October 2011, police say developments in the case led them to turn the case over to Project Kare, a police team that investigates missing or murdered women.
The team's work has led to at least two successful murder convictions in court.
Const Ray Shelton told the news conference that investigators are not releasing who made the recording of the phone call, how it was obtained, or how long police have had it.
Shelton said the audio has been analyzed by experts for clues.
"We can't call him a suspect," Shelton said of the man in the recording. "We don't even know a crime has been committed."
"We're calling him a person of interest.