A close friend and the sister of Tara Grinstead are anything but impressed after learning about a south Georgia woman who claims she's the one who led investigators to Grinstead's alleged killer.

A story aired on CBS This Morning Thursday about Brooke Sheridan who told CBS' 48 Hours that she's the tipster who cracked the 11-year-old murder mystery.

Grinstead, an Ocilla school teacher, went missing in October 2005, and her case became the biggest missing-person case in the GBI's history.

In February, the GBI charged Ryan Duke with killing her.

Ryan Duke

"She's just seeking attention," said Wendy McFarland about Sheridan. McFarland was a close friend of Grinstead's. They both taught at Irwin County High School.

Anita Gattis, Grinstead's sister, had even less to say about Sheridan.

"She's not worth it," Gattis said when asked for a response to Sheridan's story on CBS This Morning.

The GBI could not confirm that Sheridan's tip lead them to Duke or if Sheridan is eligible for the reward money associated with the case.

Sheridan told 48 Hours that her boyfriend, Bo Dukes, confessed to her that he was involved in the case.

Dukes is charged with helping Ryan Duke dispose of Grinstead's body. They're friends who were students at Irwin County High where Grinstead taught.

Bo Dukes booking photo from Friday after he was booked in connection to the Tara Grinstead case.
2001 Irwin County High School yearbook photos of Ryan Duke and Bo Dukes, side-by-side.

"I felt like I was gonna be sick. I didn't know who I was staring at. I didn't know who he was," Sheridan told "48 Hours."

Dukes confided to Sheridan that his friend, Ryan Duke, had told him that he had killed Grinstead back in 2005. Duke convinced Dukes to help him dispose of her body. Both men were former students in Grinstead's history class.

Sheridan says she asked why Duke killed Grinstead, a former beauty queen.

"He said, 'That's something that only God and Ryan know,'" Sheridan said.

She says that's when she turned in the man that she loved.

"And I knew that he would probably serve the rest of his life in jail," Sheridan said. "That family's peace to me was more important than his freedom."

She says she told Dukes, "You need to confess. You need to own to what you've done and confess.' I said, 'Because that family deserves to know.'"

"He says, 'I just want her family to know,'" Sheridan said.

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Tara Grinstead (13WMAZ file photo)