Longueuil police are ramping up their efforts in trying to find a missing mother and her baby son.

Jian Ping Li’s husband told police that when he left their Brossard home the morning of April 30 at 9:40 a.m., his wife and son were at home. When he returned around 2:30 p.m., they weren’t there and haven’t been seen since.

Their son Xiao Feng Lu was six months old at the time.

Longueuil police announced Thursday that in collaboration with Sun Youth, a reward of $20,000 will be offered to anyone who provides information that helps authorities find the duo. The reward was increased from $5,000.

Police say the reward is one of the largest ever offered in Quebec in a missing person case.

Insp. Mario Plante, deputy director of the Longueuil police service, said police have received more than 100 tips and all have been checked out, but four months after she disappeared, there are still no solid leads.

“The language barrier is one of the principle obstacles, but so far we have been able to receive a few (pieces of) information from the (Chinese) community,” he said.

When asked if he thinks Li is still live, Plante replied: “I hope she is.”

Cst. Celia Qhang, an officer of Chinese descent, has been put on the case to liaise between the force and Li’s relatives, and with the Chinese community in Brossard.

She is working the case full time, Plante said.

Qhang is the star of a 40-second, police-produced video in which she appeals directly to the Chinese community, in Mandarin, for help with the case. The video has French subtitles.

Police say Li’s husband has been collaborating in the investigation and that at this point, he is not suspect.

In July, Li’s sister and brother came to Canada from China to help with the search. Li also has family members in the United States and all are being kept abreast, either every day of every second day, of the measures police are taking.

Longueuil police has set up a command post in Brossard at the corner of Rome Blvd. and Stravinski Ave. in the hopes of collecting new leads to examine.

They are asking the public to call 911 as quickly as possible if they spot Li and her son. Anyone with information about the disappearance can call 450-463-7211.