Nancy Guthrie has been missing for more than six weeks, and authorities have still not located the 84-year-old mother or identified a suspect in what investigators believe is an abduction.

So how might the case finally be solved?

Jennifer Coffindaffer, a retired FBI agent, recently shared her thoughts on the investigation while speaking to Newsweek. According to Coffindaffer, the most likely way the mystery will be cracked is if someone who knows the person responsible comes forward with information, per TV Insider.

“I think the number one way this case is going to be solved, in my opinion, is somebody coming forward that knows him,” Coffindaffer told Newsweek. “You know, a girlfriend that gets angry at him or a family member that finds some sort of moral compass or wants that $1.2 million and finds that is worth it to go ahead and betray their loved one.”

Nancy, the mother of Today co-anchor Savannah Guthrie, has been missing since Jan. 31, when investigators believe the 84-year-old was abducted from her home in Tucson, Arizona. Since then, authorities have released doorbell camera footage showing a masked suspect and provided a description of the possible abductor.

Savannah Guthrie and her family have offered a $1 million reward for information leading to Nancy’s safe recovery. The FBI has also announced a $200,000 reward for information that leads to an arrest and conviction, including $100,000 donated anonymously.

Retired FBI agent Jennifer Coffindaffer said she believes the suspect captured in the doorbell camera footage will eventually be identified by someone who recognizes him.

“You have the ring, you had the tattoo, you have the clothing, you have the eyebrows, you have the mustache — somebody knows who he is,” Coffindaffer said. “That’s their best lead. Somebody is going to come forward. It’s just a matter of how long that will take.”

Last week, the Pima County Sheriff’s Department also addressed a new development in the case after DNA found on gloves discovered two miles from Nancy’s home was traced to a local restaurant worker. Sheriff Chris Nanos said the gloves ultimately were not connected to the investigation.

Authorities are continuing to test other DNA evidence and have not ruled out using genetic genealogy to try to identify the suspect. However, Coffindaffer noted that process could take significant time because it depends on relatives of the suspect having uploaded their DNA to genealogy databases.

Because of that, she believes the most likely breakthrough will come from someone recognizing the suspect and contacting investigators.