Lori Loughlin and Mossimo Giannulli's Home Burglarized, $1 Million in Jewelry Stolen

Lori Loughlin and Mossimo Giannulli are now crime victims ... because we've learned their house was hit by burglars who walked away with a million bucks in jewelry.

It went down January 3 ... we're told Lori and Moss were not home. The break-in and theft were discovered by a housekeeper.

Law Enforcement sources tell TMZ ... the thieves smashed a bedroom window at their L.A.- area home. They were dressed in all black and wore masks. Cops know this from surveillance cams. Once inside, they stole Lori's jewelry box which contained super-expensive bling.

Cops don't know if Lori and Mossimo were specifically targeted or if this was a random burglary.

Cops believe a South American burglary crew pulled off the heist ... apparently, they travel to America, hit locations and then quickly leave the country.

Lori's camp tells TMZ ... Lori's thankful no one was hurt. Interestingly ... Bob Saget's death helped put the burglary in perspective for her ... she says material stuff isn't the most important thing in life, it's family and love.

Since the incident, Lori has beefed up security ... they'll be there around the clock, at least for the time being.