While relatives and co-workers tried in vain to reach her, someone sold 78-year-old Robinson's car and bought another car and a van in her name, South Daytona police said. Another family was squatting in her mobile home. Someone used her ATM card.
Now, as police try to unravel the mystery of the widowed great-grandmother's disappearance and death, advocates for the elderly warn that it's easy for older people to become victims.
Like Robinson and Sheldon, many Florida senior citizens live alone, far from their families, making them vulnerable to predators who want their money.
Between July 2009 and June, the state Department of Children and Families investigated 387 suspected cases of elder exploitation in Orange and Osceola counties.
"There's a lot of bad people," said Marissa Smeyne, an Orlando-area lawyer whose specialties include elder-abuse law. "And in this economy, they look for an easy mark."
So, what can families who live far away do to keep their loved ones from being victimized?
Even if older people are mentally competent, it's still important to warn them about the dangers of being too trusting, said John Harrell, a spokesman for DCF in Volusia County.
"One of the biggest challenges is you have so many seniors who are very proud," Harrell said. "They don't want to ask for help. They may overestimate their own capacities and their own abilities."
In many cases, seniors are scammed by phony salespeople who extract their credit-card or Social Security numbers, or by unscrupulous repairmen who overcharge. In other cases, they are befriended by con artists.
Police and adult-protection workers have plenty of horror stories. In one case, an elderly woman paid $700 to have her grass cut and eventually was scammed out of $25,000. Another woman got swindled by a dance instructor who gave her flowers, then persuaded her to withdraw all her money from a brokerage firm.
Another grandmother revised her will, gave a stranger power of attorney and stopped communicating with her family out of state after he changed her phone number, said Sandi Jernigan, Seminole manager of Seniors vs. Crime, which helps older people avoid scams.
"If the older person is of sound mind, there's not a whole lot you can do," she said.
For months, Robinson's neighbor, Kimberly Smith, 44, took an increasingly larger role in her life, police say. They are investigating whether Smith influenced Robinson's withdrawal from her longtime support network of co-workers, relatives and friends that culminated in her disappearance.
The investigation took a twist Aug. 25 when officers found Sheldon's body. Detectives say Smith had been caring for Sheldon, who was divorced and estranged from his son.
Watch for warning signs
Experts advise friends and relatives to trust their gut instincts and ask law officers to make a "well-being check" if something doesn't seem kosher. Warning signs include an abrupt withdrawal from relatives and normal routines, a new friend who hangs around too much and secretive behavior.
"Unfortunately, a lot of seniors tend to be trusting if somebody is nice to them," said Marsha Lorenz, president and chief executive officer of Seniors First in Orange County. "They need the socialization, attention."
Meals on Wheels is a good way to keep tabs on isolated seniors, said Carmen Carrasquillo, chief operations officer at the Osceola County Council on Aging. Volunteers, who are screened and fingerprinted, get to know their clients and can summon help if they sense trouble, she said.
Elderly people who are competent can help protect themselves. They should not to give out too much information or let people they don't know well into their homes, said Bill Mendoza, a retired New York City police officer who volunteers with Seniors vs. Crime in Orange County.
"We need to encourage our seniors, when something seems suspicious, to get in touch with a trusted person — whether it's a child out of state or someone from church or a lawyer," Fuller said.
Relatives should watch for erratic or irresponsible financial actions. Most importantly, proponents for the elderly say, stay in close touch. Be aware of changes in mood and behavior.
If you can't visit in person, try to find someone trustworthy, such as a church member, neighbor, relative or friend, to monitor what's happening, said Harrell of DCF. If seniors agree to waive privacy protections, doctors can be a good source of information because older people tend to visit them often.
"In most cases, if you err on the side of follow-up, you have no regrets," attorney Smeyne said.
Susan Jacobson can be reached at firstname.lastname@example.org or 407-540-5981.