According to police, someone has been swiping the garments from homes overnight for nearly a year.
The thefts have all occurred at residences in the area bound by Jeanne-Mance, St. Urbain, Legendre streets and Metropolitan Boulevard.
They say the suspect returns to the scene of the theft a few months later and leaves an envelope with the the stolen underwear and an explicit photo of himself. The man appears to target women in their 50s or early 60s.
The suspect is between 20 and 30 years old, five feet eight to six feet tall and has brown hair.
One of the victims captured a video of the suspect stealing underwear on June 27. The video is now being distributed by Montreal police.
The SPVM asking anyone who has information about the suspect to contact Info-Crime Montreal at 514 393-1133.