It has been more than 80 days since Jian Ping Li and her six-month-old son Xiao Feng Lu disappeared without a trace from their Brossard, Que., home.

The 42-year-old woman and her young son were last seen the morning of April 30 at their home near the corner of Sabourin Crescent and Stravinski Avenue.

Jian Ping Li siblings

Sister Jian Ying Li and brother Jian Jun Li came to Montreal a week after their sister's disappearance in an effort to find her. Jian Ping Li and her six-month-old son Xiao Feng Lu disappeared from their Brossard home on April 30. (CBC)

According to Longueuil police, Li left behind her ID, money and other personal effects, as well as the baby stroller. It's believed she left on foot, was picked up or was taken.

Brother Jian Jun Li and sister Jian Ying Li came to Montreal from their home in China one week after the disappearance to try to find their sister and nephew.

Jun Li is a police officer in China. He and Ying Li meet with police once a week to share what information both parties have gathered. 

“Now it’s been more than 80 days since they disappeared. Because my nephew is only six months old, I know their chances of survival are quite low,” said brother Jian Jun Li in an exclusive interview with CBC News.

“This is not a runaway. After more than 80 days, I feel like this is a murder,” he continued.

Li exceptionally bright

Jian Ping Li was a gifted student from a very early age, her siblings said.

Jian Ping Li

Jian Ping Li and her infant son disappeared on April 30, leaving their Brossard home without identification, money and other personal effects. (Lirong Cheng)

She excelled in her regional exams while living in the Hunan province of China, and was admitted to a mathematics research program at the age of 16.

She was one of just two students from the province accepted to Wuhan University, one of China’s top universities.

She went on to pursue graduate studies, where she met her husband. She became a professor and eventually moved to Shanghai before deciding to head to Canada.

According to her siblings, she arrived in Canada as a skilled worker and was able to bring her husband and her eldest child, now aged nine, over from China.

Li had two more children after her husband came over in 2006. Her daughter, now five, and son Xiao Feng Lu.

'Best she's ever felt'

Li’s siblings said their sister told them she had been experiencing marital problems, but that her husband, who had left briefly, had recently returned home.

'My greatest hope is for my sister to come home safely and for the baby to come home safely, but I know that this is too much to expect.'- Jian Ying Li, sister

“She told me she was doing very well and that the worst times were behind her. She said she was feeling the best she’s ever felt,” said sister Jian Ling Li.

She told her siblings that she was doing well thanks to the support of her church and told them not to worry about her.

Her brother last spoke to her on March 29; her sister last video-chatted with Jian Ping Li on April 20.

Those are the last times they ever spoke to her.

CBC news spoke to Li's husband Hong Hui Lu at the family's home. Police say Lu is cooperating with the investigation. He said he could not do a full recorded interview because he was too upset and is caring for the couple's older children. He did say he and his wife did not have any marital issues; rather, he said, it was quite the opposite.

He said the family went to the zoo and the park often and said they were very happy.

He said that since the disappearance, his nine-year-old son cries and asks about his mother and brother every day. The five-year-old daughter doesn't quite understand, but is also upset.

Police continue investigation

Jian Jun Li

Jian Jun Li is a police officer back home in China. He said he felt police would be more successful in solving his sister's case if they had a full-time Mandarin speaker working on it. (CBC)

Const. Mark David of Longueuil police said the team investigating Li and Lu's disappearances have so have followed up on 90 tips, but that none of them have led to their discovery.

David said police have already conducted canine and helicopter searches and have involved provincial police, the RCMP and the Coast Guard. He also said Interpol was involved based on a tip that Li took her Chinese passport with her when she left her home. 

Her young son does not have a passport.

David said investigators are working with Sino-Québec, an organization that seeks to improve relations and communication with the Chinese community. They also say a Mandarin-speaking officer is helping communicate with the family but the officer is not working directly on the investigation.

David said Li and Lu's disappearances remain a high priority for Longueuil police.

Preparing for the worst

Li’s siblings and elderly parents, who remain in China, have been struggling to come to grips with her disappearance.

“I haven’t been able to sit still. I’m restless. I haven’t been able to sleep or eat,” said brother Jian Jun Li.

Li’s family members are preparing themselves for the worst, but hoping for the best.

“My greatest hope is for my sister to come home safely and for the baby to come home safely, but I know that this is too much to expect,” said sister Jian Ying Li.

“I want to see my sister alive, but if not, then I would at least like to see her body. I’m very determined,” her brother added.