(CBS/AP) Patricia and Joan Miller were identical twins who pursued their dreams together. As a team, the Miller sisters met Bing Crosby, appeared on a TV show in the 1950s and purchased a house in California's picturesque South Lake Tahoe.
Their shared life ended in a mysterious double-death at their home last week. One body was in a downstairs bedroom, and the other was in the hallway just outside. They were 73.
Medical investigators have not been able to determine how or when the women died, but their decomposed bodies suggest they had been dead for at least several weeks when they were found, said Detective Matt Harwood with the El Dorado County sheriff's office. Toxicology reports likely won't be available for at least two more months.
There was no blood, no signs of struggle. Nothing indicated that the women -- who had danced for Crosby in their younger days -- had persistent health troubles. Their longtime home was not unkempt, a likely sign of mental or physical illness.
It was as if the two sisters, long each other's only companion, could not live without each other, Harwood told The Associated Press.
"My perception is one died and the other couldn't handle it," said Harwood, who has been unable to find any close friends or family members of the twins. "It appears purely natural, but we are still trying to piece it all together."
Investigators hope to soon narrow down when the sisters died. It's unlikely carbon monoxide poisoning, a common danger in the winter, is to blame because a window had been left open and the house was well ventilated.
Police usually do not release the names of the dead without first informing their relatives, but the sisters' shrouded lives made that impossible, Harwood said. Even after widespread media reports of their deaths this week, no relatives have come forward, Hardwood said Wednesday.
Never married and without children or pets, the Miller sisters had long withdrawn into the four-bedroom home they purchased in 1976. When people called, the sisters came up with excuses to get off the phone. Without explanation, they stopped sending birthday cards to a childhood friend. And on the rare occasion when they left their home, the two women didn't chat up the neighbors.
"The circumstance surrounding their death is somewhat of an enigma," Harwood said. "These two only ever had each other, and we would like, at least for their sake, to notify their family."
A neighbor spotted an ambulance at the house a year ago and assumed the sisters had fallen ill. Someone asked police to check regularly on the house. When officers arrived Feb. 25 for a routine check, no one answered the door. The next day, police forced their way in and found the bodies.
As news of the deaths spread, former South Lake Tahoe residents called police to report that they had lived near the sisters for decades in some cases, and had hardly seen them. One sent in a postcard that claimed the sisters were the only remaining members of their family after their mother's death and their brother died at war.
Calls Tuesday to several longtime residents and social groups in the area turned up little, as many community leaders said they had never heard of the sisters.
Joan Miller was a senior accounting clerk in the payroll department at the Lake Tahoe Unified School District from 1979 to 1984. Patricia Miller, who drove a white convertible with red upholstery, worked in the El Dorado County's social services office during that same time.
"I never heard of anyone else being in either of their lives," said Betty Mitchell, 89, who supervised Patricia Miller in the social services office and saw the twins around town. "They were inseparable and really identical."
The sisters were friendly and often told stories of their singing adventures. They told Mitchell they had performed at Yosemite National Park and when their mother came to visit from Oregon, they all dined at Mitchell's home.
But the sisters were also guarded. When Mitchell urged them to join a community choir, they declined. They never discussed their social lives.
"They kept things to themselves," Mitchell said. "I don't even know if they had siblings."
The Miller twins were the daughters of Fay Lang and Elmon Gordon Miller, who went by the name "Bud" and was born in 1895 in Bremen, Kentucky, Harwood said. He was a dairy salesman in Oakland at one point.
The sisters grew up in Portland, Ore., before moving to the San Francisco area, where Joan Miller attended college. The women briefly appeared on a 1950s television show called the "The Hoffman Hayride" and posed for a picture with Crosby as children. The twins also entertained troops at military bases, a childhood friend told Harwood.
The sisters never seemed interested in dating or expanding their social spheres. They listed each other as their next of kin, Harwood said.
"All they had was each other, and that's actually the way they wanted it," he said.
Joyce Peterson of the International Twins Association, a social group based in Oklahoma, said she once heard of 100-year-old twins who died within days of each other.
"As a twin, you've got this bond, you're close -- almost like a married couple," said Peterson, of Minnesota, who serves as co-vice president of the group with her identical sister.
The Miller twins appeared in poor health recently and possibly had been treated a year ago for dehydration or malnutrition, Harwood said.
Neighbors would call and the sisters would say, "Let me call you right back," and then wouldn't.
"They weren't taking care of themselves as they should or could have," Harwood said.