Patricia Ann Kucerovsky, a 43-year-old mother of two and a school teacher, had very significant levels of mercury in her system when she died in 2008. (CBC)

The Fredericton Police are asking for the public's help in solving the four-year-old homicide of Patricia Ann Kucerovsky.

The 43-year-old woman died of mercury poisoning in 2008.

Last year, investigators determined her death was a homicide. No charges have been laid, but police do have a suspect in mind.

On Thursday, Const. Danielle Carmichael told a news conference that police have done all they can to catch the killer and information from the community could be what solves the case.

They are hoping someone comes forward with information about the death of Kucerovsky, who was a mother of twin boys and a school teacher.

The news conference comes on the heels of a vigil held last weekend by relatives and friends of Kucerovsky to mark the anniversary of the her death.

They called for more to be done to find out who killed her and to bring the person or persons responsible to justice.

Fredericton Police Const. Danielle Carmichael says even a seemingly small detail could be significant to the investigation. (CBC)

Carmichael says the vigil may have helped bring some details to mind.

"That's what we're hoping, from the vigil, from our release today and again with Crime Stoppers, that it will get the community talking and discussing the case again and hopefully we'll have new leads from that," she said.

"It could be that someone doesn't believe that what they know is significant because we're dealing with a homicide.

"But maybe when all of this comes to light, when they see the Crime Stoppers case of the week, when they heard about the memorial — it's generated a lot of discussion and maybe they're having a second thought and thinking, 'You know, it may seem small to me, but it may be quite significant to the police.'"

Complex case

Kucerovsky's death at the Dr. Everett Chalmers Regional Hospital on Aug. 19, 2008, was initially attributed to an illness. But the police began quietly investigating the case three days after her death.

In March 2010, her death was deemed "suspicious" and by December 2011, it was ruled a homicide — Kucerovsky had been poisoned.

She had "very significant" levels of mercury in her system, police had said, calling the case "very complex."

Mercury poisoning damages the central nervous system and the kidneys and in heavy exposure it can cause brain damage and ultimately death.

Details about how much mercury was in Kucerovsky's system or how it was administered have not been released.

A 44-year-old man was arrested in connection with the case in November 2011. He was subsequently released unconditionally, but police said at the time he was still considered a suspect.

He remains the only suspect, police said.