JOE ZAVALA SAT BEHIND THE WHEEL OF HIS 1961 CHEVROLET Corvette, cruising along Interstate 95 to Quantico, Virginia, at a safe ten miles over the speed limit. The convertible top was down, the powerful V-8 engine under the hood purred like a contented tiger, a CD of Ana Gabriel was playing, the wind was blowing in his dark brown hair, he was on the NUMA payroll, and he was about to meet a beautiful woman. Life was sweet.

Around forty miles southwest of Washington, he turned off the highway onto a tree-shaded road and drove through countryside that first offered glimpses of military vehicles and structures, then led to a checkpoint manned by an armed guard. He showed the guard his NUMA credentials, had his name matched against a visitors’ list, and followed the signs to the main building of the FBI Academy.

Surrounded by three hundred eighty-five acres of woods, the Academy was built on the Marine Corps base in the 1970s under the reign of J. Edgar Hoover. The campus-style complex consisted of twenty-one buildings of a soothing honey color connected by a network of glass-enclosed corridors.

Zavala went through the front entrance of the main building and walked past a bubbling fountain into the atrium lobby. He checked in at the reception desk, and said he had an appointment with Agent Caitlin Lyons. He was given a security badge with his name on it to wear. A young woman was assigned to guide him through the maze of buildings and corridors.

He heard a commotion that sounded like a gunfight at the O.K. Corral and knew that he was near the shooting range. The guide ushered him in and pointed to a row of booths.

“Number ten,” she said. “I’ll wait outside for you. Gets a little noisy in here. Take your time.”

Zavala nodded his thanks, and took some ear protectors from an attendant. Then he went over to a booth and stood behind a woman who was firing at a silhouette of a man. She stood with her pistol in both hands, slowly and methodically pumping bullets into the target, hitting it in spots that would have proved fatal had the bullets been perforating human flesh instead of paper.

Zavala had no desire to startle a trained FBI agent while she had a gun in her hand. He stood behind her patiently until she turned and saw him. She beckoned for him to step into the booth. She replaced the spent magazine with a full one, handed him the pistol, and pointed toward the target.

The Walther PPK was a favorite of Zavala’s, and the grip felt comfortable in his hand. He raised it to eye level, flicked the safety off, and let off six shots in rapid succession. Every squeeze of the trigger found the center circle of the bull’s-eye over the heart.