Liliane Cyr had been quietly confident that the targeted search would provide answers to the mystery of what happened to her 18-month old daughter Yohanna in 1978.
Those hopes were dashed when Montreal police emerged from digging up parts of a parking lot to say they had found nothing.
Cyr had left Yohanna in the care of a boyfriend for one week while taking a job outside Montreal. Her daughter was declared missing on Aug. 15, 1978.
The boyfriend eventually told Cyr the girl had drowned in the bathtub and that he'd buried the body.
The corpse was never recovered and charges against the suspect were stayed due to a lack of evidence.
Yohanna's case was re-opened several years ago and police were acting on a tip that a neighbour reported seeing a man matching the boyfriend's description carrying a metal box toward a vacant lot in the city's St-Laurent borough.
The area was developed and now houses a municipal recreation centre and parking lot. On Friday, police dug in two specific spots identified by engineering students who used sophisticated tracking equipment earlier this year to trace metal in the lot.
The lead detective said they were looking for a metal box — about the size of a bread container — they believed might contain the girl's remains.
"I feel very sad for the family," Det.-Sgt. Marie-Julie Durand told reporters. "Even if we knew from the outset that there was a big chance we wouldn't find anything, we had to validate the information we had."
Durand said Cyr's disappearance remains an active case. She began reworking it from scratch in 2011, but conceded that police have gone as far as they can without another public tip.
Cyr's disappearance is one of Quebec's oldest documented missing children's cases and involves the youngest person to have vanished.
"The case is not closed," Durand told reporters. "We would invite anyone who knows anything to come forward."
Earlier on Friday, Cyr stood in the parking lot and was optimistic. She wasn't sure how she'd react if police turned up any remains. Until three years ago, she'd held out hope Yohanna would turn up alive. Now she wanted closure.
"It's got to finish, it's got to be the end," Cyr told The Canadian Press before police finished their search. "Find a piece of bone or something else, to bury my daughter somewhere else so she can rest in peace."
It has been a difficult three-plus decades with many ups and downs. At one point in 2005, authorities thought they'd found Yohanna — a woman who looked like her was living in California and searching for her birth parents.
"I thought that was it," Cyr said, who was disappointed when DNA results proved negative. In 2013, an age-advanced sketch of Yohanna Cyr was released.
The head of the Missing Children's Network said it's still important the family knows what happened.
"It's extremely difficult for her, her heart is broken, it's not the response she was hoping for today," Pina Arcamone said.
The main suspect, the former boyfriend, an American, is still alive and refuses to co-operate with authorities.
"I met him two years ago in the United States and he doesn't want to give information," Durand said.
She said the man, now in his late 60s, was given numbers where he could remain anonymous and provide information that could lead to the body.
Follow (at)sidhartha_b on Twitter