Barely recognizable as a full-size car, the rusted hulk of a 1960s Chrysler sits on the back of a flatbed truck near Penticton, B.C. ((CBC))

The skeletal remains found in a car pulled from the bottom of a B.C. lake last week are those of a young mother who disappeared nearly four decades ago.

Betty Thomas, 20, disappeared in November 1972 without a trace, mystifying her family and leaving behind a husband and an 18-month-old son.

According to her cousin, Carol Thomas, police looked into the disappearance but found no clues, and the family spent the next 38 years wondering what had happened to the young woman.

But then last week, an old Chrysler was pulled out of Skaha Lake, south of Penticton in the Okanagan, by a team of divers conducting a cleanup of the lake. When the car was flipped over on shore, some bones fell out, including a small skull.

When Carol heard the news, she immediately had a feeling the decades-old mystery was about to be solved.

"I don't know why I said it, but I just, I had this feeling, I said to somebody, 'I wonder if it's Betty'," she told CBC News on Friday.

Her hunch turned out to be right. Earlier this week, police notified the family that a laminated birth certificate and other personal identification found with the body indicated that the remains were Thomas's. The car, a Chrysler New Yorker, was identified as belonging to her husband.

Her son, Gordon, now nearly 40, also followed the news of the body in the car pulled from the lake. He told reporters he was shocked when police called him at his Surrey home with the news earlier this week.

Police said it appears Thomas died after the car left the highway and dropped about 100 metres into the lake, located about 250 kilometres east of Vancouver.

While the actual circumstances leading up to Thomas's death may never be known, for Carol Thomas, it's a sad ending to a 40-year mystery that does at least provide some closure.

"It's just kind of a relief, sort of, after all this time, you know," she said. "I mean, it's a tragedy how it happened, but it's kind of a relief to know that she has been found now."