There are relatively few "whodunits" in real life. But in 1972, in the Gold Coast area near Lake Minnetonka, a rare kind of caper was pulled off that caught national attention and was never solved.

A rich socialite, Virginia Piper, was kidnapped from her home by two masked gunmen. She was blindfolded and driven to a forested area outside of Duluth, where she was handcuffed and chained to a tree. The 49-year-old Piper was rescued by FBI agents two days later, after her husband, Harry Piper Jr., paid a $1 million ransom.

Nobody was convicted of the kidnapping. And the ransom — valued at $5.5 million in today's dollars — was never recovered.

In "Stolen From the Garden," William Swanson, the author of two previous accounts of celebrated Minnesota crimes, turns to the story of the Piper kidnapping, and to the exhaustive but futile efforts of the FBI and federal prosecutors to solve the crime.

Swanson gives a detailed retelling of the kidnapping and the harrowing ransom drop-off procedure that Harry Piper went through to get his wife back. Cooperation from the Pipers' sons enables Swanson to give an insider account of the family's ordeal and access to FBI files on the case obtained by the son, Harry Piper III, after court battles with federal officials.

The story has plenty of strange twists and turns as well as a cast of colorful characters. They include Kenneth Callahan and Donald Larson, who were tried twice but acquitted both times of the kidnapping, and the attorneys in the case: prosecutor Thor Anderson and defense lawyers Bruce Hartigan and Ronald Meshbesher.

More than three decades later, the three attorneys are still arguing about the trials. Anderson maintains that there is no mystery about the kidnapping. The feds prosecuted the right guys, he says, but the jurors who acquitted Callahan and Larson made a mistake. Case closed.

Meshbesher still indignantly claims that the FBI "phonied up" fingerprint evidence against his client, Larson, to get a conviction in a high-profile case. The FBI's forensics team tried and failed three times to get a fingerprint match, but claimed they got one in 1977 just before Larson and Callahan were indicted — 16 days before a federal statute of limitations to bring charges expired.

Hartigan makes similar claims about the FBI's purported match of a hair sample implicating Callahan.

If Callahan and Larson were the kidnappers, there is no evidence they lived high lifestyles after the 1972 crime.

By the time of the first kidnapping trial, Larson was in prison for the murders of five people in one bloody incident: his girlfriend, her lover and three children.

After his acquittal, Callahan lived a quiet and seemingly simple life as a carpenter in Cumberland, Wis., where he became friends with several local police officers.

So, if Callahan and Larson didn't kidnap Virginia Piper and get rich, who did?

Swanson and the people he interviewed who were involved in the case offer theories and possibilities. But that's it. What we do know, Swanson says, is that the FBI spent many times more money trying to solve the crime than the kidnappers got in a large 110-pound duffel bag stuffed with $20 bills.

Paul Gustafson is a former Star Tribune reporter who served as an executive assistant to Ramsey County Attorney Susan Gaertner.