Divers found McCarthy's body late on the night of April 17, more than six days after she left a friend's cabin near Badger.
However, the key factor in finding McCarthy's body came from a family-organized effort that used a GoPro camera that allowed glimpses into the murky, ice-covered waters of Paul's Lake.
Stepson Shawn McCarthy said the family thinks the RCMP gave up too quickly in the initial stages of the search, after Margaret McCarthy went missing in the early hours of April 11.
"The dive master, when he was on scene he shook most all of our hands and he said, 'I will not leave until I am told to leave,' but 24 hours later he says, 'I'm calling this off,'" he said.
When the RCMP called off the search, Shawn McCarthy said the family wasn't ready to give up.
He said family and friends drilled holes throughout the ice and enlisted volunteer help.
"A friend of ours had purchased a GoPro camera, hooked it up on two eight-foot lengths of plastic conduit, put it down through the holes, was viewing 20 to 25 holes at a time, went back to a friend's shed and reviewed it on his laptop," McCarthy said in an interview.
The practice proved fruitless — until the team made one last attempt at larger holes that had been drilled for a Gander dive company that was set to arrive the next day.
"It was the last 15 seconds of video that we located her," said McCarthy.
Her body was recovered the following day, bringing relief to the family.
"Just to put closure to it," said McCarthy. "Any family who's out there who has gone through it knows exactly how the family felt, and we just felt we had to find her."
According to McCarthy, the private dive company offered the service without charge and various groups, companies and residents did more to help than police searchers.
He added that the family is speaking out to ensure other families in future don't end up in the same situation.
"If the RCMP do show up to do a job, show up with the right equipment, train personnel if the personnel aren't properly trained to dive under ice — we don't know if this is the case, but you know, I think a few things need to be reviewed after this tragedy."
The RCMP say they completed a professional investigation and offer condolences to the family.