05/25/2012 10:45 EDT | Updated 07/25/2012 05:12 EDT

Mysterious photos may shed light on 2004 Quebec homicide

Police in Laval, Que., have released a series of mysterious photos they hope may be the key to solving another mystery – who killed Nadia Panarello?

The photos, which show a man and woman seemingly on vacation, were left in the mailbox of Panarello’s mother in the hours after the woman’s body was found in her home in 2004.

The photos were likely hand delivered, Laval police said, not sent through the mail.

However, more than seven years after 38-year-old Panarello was found dead, police haven’t figured out the link. Adding to the mystery, her family doesn’t recognize anyone in the images.

“Our detectives have met with family, friends and, up to now, we have nothing,’ said Const. Franco Di Genova of the Laval police. “We want to identify who these persons are – if they're related with the family, do they have anything to do with this murder."

He stressed the people in the photos aren’t considered suspects.

Panarello’s family last saw her alive when they left home as usual on the morning of Feb. 12, 2004.

However, the mother of two never arrived at work. Family members went home to check on her and found her dead on an upper floor of the Vimont-area home.

Police have identified some suspects in the killing, but have never made an arrest.

Investigators are asking anyone with information to call 450-662-4636.