DOUGLAS (CBS) – Bonnie Kiernan is convinced her sister’s killer, Rodney Stanger, is involved in the disappearances of Molly Bish and Holly Piirainen.

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Investigators are looking into whether some of the personal items found in the Florida home of Stanger are related to the Massachusetts cases.

Stanger is now jailed in Florida after the brutal murder of his longtime girlfriend, Crystal Morrison, Kiernan’s sister.

WBZ NewsRadio 1030’s Kim Tunnicliffe reports

Stanger was labeled a person of interest in the Bish case after investigators learned he lived hunted and fished not far from the Warren pond where the 16-year-old lifeguard was abducted in 2000, and the Palmer woods where her skeleton was later found.

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When Kiernan was recently going through her sister’s belongings in a trailer that Morrison and Stanger shared, she found things that led her to believe Stanger was involved in the Massachusetts cases.

“There were an awful lot of hair-ties, scrunchies, and barrettes that wouldn’t fit my sister’s age,” says Kiernan. “At 50-years-old you’re not going to be wearing a 12-year-old’s barrette.”

Kiernan also found a wallet with a Firearms ID card renewed just before the Bish murder. It features a Stanger photo with a striking resemblance to the sketch of a mystery man who was seen near where Bish was abducted.

Kiernan also says she received a cryptic message from her sister right before her violent death which indicated Stanger may have been involved in the disappearance of Bish and Piirainen. She says Crystal asked her about her bird named Molly and then whispered the word “murders” into the phone.

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Massachusetts State Police took many of the items to the state crime lab for testing.