Dillard faced four to six months in jail after her conviction in California, and when she was released, she transferred her probation to Oregon. Sgt. Thompson, of the Washington County Sheriff's Office in Oregon, believes she was able to find work as a medical assistant at Oregon Pediatrics because she began using the last name Dillard instead of Lubin.
"What could have easily happened was if they did a background check and they did a criminal check with that name the conviction wouldn't show up," Thompson said.
Psychiatrists and hospital workers who monitor child abuse say "medical abuse" can be some of the most difficult cases to detect -- and the most difficult to prove.
"We usually have a few suspected Munchausen by proxy cases ongoing all the time," said Allison Scobie, director of the Child Protection Program at Children's Hospital Boston.
"A child can remain in the care of their parents, and then we have a suspicion of what could be called medical child abuse," she said. "That's also what we call Munchausen's. Being able to intervene and convey that to authorities can be a very protracted process."
Scobie, who runs the Child Protection Program at Children's Hospital in Boston, has seen a wide spectrum of "medical abuse," from parents dousing their children's diapers with juice and calling it blood, to a mother so insistent that her child was in pain that she convinced doctors at a nearby hospital to operate on the appendix.
"But when it came out, the appendix was perfectly healthy," said Scobie.
She said it can be difficult to prove a case of medical abuse even when doctors suspect it because cases of Munchausen by proxy often start with a real medical condition that the parent then begins to exaggerate, or manipulates into a more serious situation.
"It can take years because sometimes this happens quite gradually," said Scobie. "But it's actually one of the most lethal forms of child maltreatment."
Feldman, the author of "Playing Sick," said up to 9 to10 percent of all Munchausen by proxy victims die as a result of the medical abuse. Often the perpetrators are in such denial they will not admit guilt even when presented with videotapes of them poisoning their victims.
"Unfortunately, the penalties for Munchausen by proxy behavior, when it's perpetrated by a woman, tend to be minimal, they tend to be slaps on the wrist," said Feldman, who added that 95 percent of the cases tend to be women.
To make matters worse, psychiatrists say they have a hard time understanding Munchausen's syndrome, and therefore can't catch it or treat it.
"We have no idea how common it is," said Dr. Thomas Wise, chairman of American Psychiatric Association's Council of Adult Psychiatry and professor at Johns Hopkins University School of Medicine in Baltimore.
"They [people with the disorder] don't have schizophrenia or bipolar disease. These are lonely, very disturbed people," said Wise.
He also said doctors have noticed that the Munchausen by proxy commonly coincides with a serious personality disorder, "but what it shows is how we really don't understand the full spectrum of personality disorders."
Wise's best advice in cases of Munchausen by proxy is for people to protect others and separate children or people who need care from the perpetrator.
"With the Oregon case, it absolutely boggles one's mind that it [the previous conviction] had no effect on her," said Wise. "It shows how resistant people are to this treatment."