The FBI is closing in on a key suspect in the kidnapping of a Florida pilot who mysteriously vanished from his office nearly a year ago.

Federal agents believe Robert Wiles was abducted last April after going to work at his family's aviation business, the National Flight Service, in Lakeland, Fla.

Two days later, relatives found a ransom note demanding money.

FBI Special Agent David Couvertier said investigators believe the suspect knows Wiles.

The person is likely "someone who was complaining about Robert, jealous of him ... and was almost obsessed with him," Couvertier told FOX News.

The FBI says Wiles' family tried to comply with the ransom request. Rewards of up to $250,000 have been offered for information leading to an arrest and conviction.

Agents believe they are now close to solving the case.

"The investigation has identified individuals of interest and a key suspect," Couvertier told FOX. "We have no information to indicate that he is deceased."

The key suspect and persons of interest live or work in Lakeland, Orlando or Melbourne. Their names were not released.

Click here for more on this story from MyFOXTampa.com.

The Associated Press contributed to this report.