Liliane Cyr’s 18-month-old daughter Yohanna went missing 35 years ago. Thanks to advanced technology, she may get the answers she has had to live without for decades.

“Every day you fight. You ask yourself where she is, what she’s been doing, is she alive, is she dead,” Cyr said.

''It's time for me to find out about my daughter — alive or dead,' - Liliane Cyr, Yohanna's mother'

Cyr was 19 years old when Yohanna disappeared in 1978.“Since 35 years, I exist — I don't live. I just exist. I have to put a mask on my face just to live.”

Cyr had gone to work, and left Yohanna in the care of her then-boyfriend. That was the last time she ever saw her toddler.

Cold case re-opened

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Last summer, police released an age-enhanced photo of what Yohanna Cyr may look like if she is still alive. (CBC)

It’s a case of twists and turns — a boyfriend accused, then acquitted and the case gone cold.

A neighbour had told police she remembered seeing a man leaving Cyr’s building with a bread box in his arms.

Police re-opened the case in 2011, and looked at aerial photos of a space in the neighbourhood that used to be a field.

Today that land is the parking lot of the Saint Laurent Recreational Centre on Grenet Street.

A police investigator with a background in engineering suggested new technology would allow police to find out what is lying several metres below the surface.

They enlisted hi-tech help from a geological-engineering team at École Polytechnique. Students and their professor recently surveyed the parking lot.

“We use a GPS to get the position right … We are looking for a magnetic target and conductive target so we use a magnetometer and metal detector,” said Prof. Michel Chouteau.

Chouteau said even if the ground has shifted, his team can still detect something underground.

“We found small anomalies, among other anomalies we know that are there. Because of lampposts, there are cables.”

Chouteau said once those the anomalies are identified and ruled out, they'll have a better idea of what is underground.

Scans of the parking lot are being analyzed.

“I hope the answer is going to be that they can dig the ground,” Cyr said.

The Missing Children’s Network has been working on Yohanna’s case for years and has high hopes for this latest effort.

“There is a secret that has been buried for the last 35 years. Maybe we'll be able to uncover this and finally give this family the answers they've been seeking,” said Pina Arcamone, director general of the Missing Children’s Network.

Over the years, Cyr has had some false alarms. In 2005, police thought they had actually located her daughter and introduced the two.

“We went dancing, laughing and I thought she was my daughter for real,” Cyr said.

A DNA test proved it was not Yohanna.

This time Cyr said she’s convinced she’ll get answers.

“After 35 years, it's enough. It's time for me to find out about my daughter — alive or dead."

The university engineering team is analyzing data from the parking lot and writing a report, which should be complete within three weeks.