PROVIDENCE — Lucia Caito, 96, of Cranston, was brought to the Rhode Island Hospital emergency room for a heart ailment Thursday. The woman, who was transported in a rescue truck from her doctor’s office in East Greenwich, was wearing jewelry.

Some time that night, according to a complaint to the police and hospital security yesterday, a man dressed in the blue hospital smock of an employee came to her bedside. As Caito lay in a bed in a small room in view of the emergency-room desk, sick and vulnerable, the man used lubricant to slip two valuable rings from her hands.

We have to take these rings for safekeeping, the man assured her, according to Caito.

The rings, which Caito’s daughter says are worth thousands of dollars, are now missing and presumed stolen.

“I’m outraged,” said Elinor Thompson, Caito’s daughter. “You’d think Rhode Island Hospital would be a safe haven for someone with heart problems.” The insult inherent in the incident is more troubling than the dollar value of the rings, which also had great sentimental importance to her mother, Thompson said.

Nancy Cawley, a hospital spokeswoman, said the hospital is cooperating with a police investigation.

“Hopefully, this will be resolved,” Cawley said.

Thompson said the robbery either was “an inside job” by an employee or was committed by someone posing as an employee who gained access to her mother due to lax security.

Cawley said the hospital would not comment on its security procedures.

The episode began to unfold at about 5:30 p.m. Thursday, when Caito, who is hard of hearing but remains active as a concert pianist, arrived in the emergency room. She was joined by Thompson, who said she had failed to coax her mother to surrender her jewelry before she was placed in the rescue truck.

On her left hand, her mother wore a wedding band and a ring with two white diamonds, one 1 karat and the other 1.25 karats, according to Thompson. The former was an engagement diamond and the other a 50th-anniversary stone. On her right hand, her mother wore a birthday ring encrusted with emeralds and diamonds, Thompson said.

When a phlebotomist came into the elderly woman’s room to draw blood, she urged Caito to give up her necklace, bracelet and watch because, she said, they could not stay on during an X-ray. Thompson said she took them, but that there was no mention of the rings and wedding band, which remained on her mother’s fingers. Thompson left at about 9 p.m. to tend to her disabled husband and elderly father at home, expecting that her mother would be admitted to the hospital.

At about 1:15 a.m., Thompson received a telephone call from a hospital nurse. Did she have her mother’s rings, the nurse inquired. Thompson promptly returned to the hospital to calm her “hysterical” mother, who was still in the emergency room.

Thompson, who made formal complaints to the police and to the hospital security staff, said the thief left a note behind with a handprinted message: “Your daughter took your rings with her so they wouldn’t get lost.”

While Thompson is pleased with the after-the-fact response of hospital security, she remains appalled.

“If it happened to my mother, who else did it happen to,” she wondered aloud.

gsmith@projo.com