ST. THOMAS, Ont. -- A nurse who killed elderly patients in her care was the subject of multiple complaints but was given a positive reference letter and went on working until she confessed her crimes, documents filed at a public inquiry examining her actions show.

The probe examining the circumstances that led to Elizabeth Wettlaufer's actions began Tuesday in St. Thomas, Ont. The southwestern town is not far from the communities where the 50-year-old injected more than a dozen patients with overdoses of insulin while working at long-term care homes and private residences for nearly a decade.

Documents submitted as evidence to the inquiry show complaints about Wettlaufer began at the start of her career in 1995, and continued until she admitted in 2016 to killing multiple patients.

The complaints range from the mundane -- that Wettlaufer had been eating her patients' food -- to the more egregious: that she made medication errors and harassed people.

Despite those issues, the documents show Caressant Care --one of the facilities where Wettlaufer worked -- paid the nurse a $2,000 settlement and gave her a reference letter as part of an agreement worked out after she complained about being fired for giving a patient the wrong medicine: insulin.

The letter of recommendation suggests Wettlaufer was a model employee who left the company to pursue other opportunities, the documents at the inquiry show.

In spite of having been fired twice -- the first time in 1995 after she took drugs from her employer in an apparent suicide attempt, according to information at the inquiry -- Wettlaufer's crimes went undetected, and only came to light when she confessed them to mental health workers and police.

She then pleaded guilty to eight counts of first-degree murder, four counts of attempted murder and two counts of aggravated assault, and was sentenced last summer to life in prison without parole eligibility for 25 years.

A lawyer representing the families of several of Wettlaufer's victims said his clients hoped the inquiry would prevent such crimes in the future.

"The idea that (the victims) were killed when they were in their most vulnerable states has shocked the province," said Alex Van Kralingen. "Put bluntly, my clients want to ensure that this never happens again."

Outside the inquiry, the son of a man killed by Wettlaufer said he wanted those who failed to prevent his father's death held to account.

"I want to see the health system revamped -- nursing care, senior care," said Arpad Horvath Jr. "But mostly I want to see the people who are accountable be crucified in the public eye, online and everywhere."

Inquiry commissioner Eileen Gillese said the probe will seek to answer what failings allowed Wettlaufer's crimes to take place, and what can be done to prevent similar tragedies in the future.

"We can begin to heal the moment we begin to feel heard," Gillese said in her opening statement, citing a quotation sent to her by a friend. "In many ways that is what our inquiry is about. Healing our broken trust in the long-term care homes system."

The commission's legal team reviewed more than 41,000 documents and interviewed experts and dozens of other people, she said.

Mark Zigler, co-lead counsel for the commission, noted that the inquiry is timely.

"We are dealing with an aging population," he said. "There's greater and greater demand for these types of (long-term care) facilities."

There are 627 long-term care homes in Ontario, and nearly 79,000 beds, Zigler said. Those numbers have not grown significantly in recent years, he said, although demand has escalated.

Some of the people and organizations with permission to call and question witnesses at the inquiry include one of Wettlaufer's surviving victims, family and friends of those she killed, and advocacy and health-care organizations.

Later this week, the inquiry will hear from three employees of Caressant Care Woodstock, the facility where Wettlaufer worked when she committed many of her crimes.

On Tuesday, the lawyer representing the company suggested those employees were also, in a way, victims of Wettlaufer's.

"A group of health-care workers were utterly betrayed by a fellow health-care worker, who was working with them side-by-side to accomplish -- they thought -- the same goals," David Golden said.

Wettlaufer herself does not have to appear before the inquiry. Gillese ruled that the 50-year-old would not be compelled to testify, supporting a recommendation from commission counsel, but her confessions were submitted as evidence to the inquiry.

Gillese is expected to release her final recommendations by July 31, 2019.