CALGARY -- After investigators received new information, the death of former Calgary Stampeder Mike Labinjo has been deemed suspicious, police said Monday.

Labinjo was found dead in his home on Sept. 21, 2018 and the circumstances of his death weren't believed to be criminal in nature, police said at the time.

Family members reported many of his personal belongings were missing from his home after his death, however, and a theft investigation revealed that numerous items and sports memorabilia had been stolen. 

"Most notable are two distinct football championship rings with the name "LABINJO" written on the side," Calgary police said in a statement released Monday.

Neither ring has been recovered.

Police are now asking for help to identity four suspects believed responsible for the theft of the rings.

Labinjo's mother, Margaret Labinjo, spoke at a press conference Monday and urged anyone with information to come forward.

"He was a brother, a father, an uncle, a cousin, a friend to many people who loved him dearly. He was a gentle soul, a hardworking, kind young man who knows how to put a smile on anyone's face if they're not having a good day," she said.

"You did not deserve to die this way. I'm going to make sure whoever did this to you are held responsible. I will fight to the end for justice to be served ... if you are in any way responsible for what happened to Michael, please, I'm begging you, turn yourself in to Calgary police." 

His brother, Randy Labinjo, described him as "caring, kind, loving and gentle."

"To me, he was my brother, I love him. When I lost him, I lost part of myself," he said.

Labinjo’s estate has also launched a lawsuit against an insurance company for $67,000 though it’s not clear what the basis of that suit is.

A defensive linesman, Labinjo played for the Stamps from 2007 to 2010, winning a Grey Cup with the team in 2008. Labinjo starred in both the western final and the Grey Cup game, where he had three tackles, one sack and four pass deflections.

Anyone with information is asked to call police at 403-266-1234, the homicide tip line at 403-428-8877 or Crime Stoppers at 1-800-222-8477.