The Brossard woman and her six-month-old son went missing at the end of April.
On that day, Li left behind her ID, money and other personal effects, as well as the baby stroller.
On Thursday, Longueuil police said that despite all the steps the force has taken to find Li and Lu, they have so far been unsuccessful.
They enumerated all the methods they've so far employed in their search, including helicopter and Coast Guard searches.
Investigators have also worked closely with the local Chinese community in hopes of finding new information that could lead to their discovery.
Brother Jian Jun Li and sister Jian Ying Li even came to Montreal from their home in China one week after the disappearance to try to find their sister and nephew.
Brother Li, a police officer in China, said he believed his sister had been killed.
Now officers are now looking for new clues to help solve their disappearance.
Sun Youth put up a $5,000 reward shortly after Li and Lu disappeared from their family home on April 30. They said on Thursday the offer has been increased to $20,000.