“The engine went at about the same time, and we think the plane was between a thousand and fifteen hundred feet high at that point.”

Howard heard the woman make a disjointed Mayday call, but there was no reply.

“She put out a distress call on the emergency frequency and set her transponder to the emergency code: that’s how the local Flight Service Station got her position.” Sheldon’s voice was clinical and detached.

The engine noise died and the camcorder must have moved again because Howard could see the ground rushing up.

Howard listened as the boy began to scream and his mother tried in vain to calm him down. The last thing she said was “Please God, no . . .” and then there was a sickening crash, and the sound of metal grating and what sounded like the wind.

“At this point the plane is down and the occupants are dead. The camcorder continued to record for a further twenty minutes until it came to the end of the tape. You might as well switch it off now.”

Howard leaned forward and pressed the ‘stop’ button. Just before he did he thought he heard the boy call out for his father but it could have been the desert wind.

“Luckily they didn’t hit the fuel tanks. When the local sheriff got there the camcorder was intact. What you’ve got there is a copy we made. The original is in one of our labs in Washington.” Howard sat down and toyed with the cassette as he listened to Sheldon. “The towers you saw in the video had been pulled down and set on fire by the time the sheriff got there. All the vehicles had gone. There’s no sign of it in the video, but we suspect they also had a helicopter. The investigation you’ll be leading is unusual in that we’re not actually concerned about the victims in the case. All the signs are that they were merely innocent bystanders, in the wrong place at the wrong time. What we want to know is who those people were in the desert, and what they were doing.”

“So it’s not a homicide investigation?” asked Howard. He couldn’t get the woman’s voice out of his head. Trying to reassure her son as the plane plunged to the ground. He shivered.

“Those men weren’t shooting duck out there,” said Sheldon. “They’d spent a lot of time and money setting up those towers, they were obviously rehearsing something. It was a practice run for an assassination. And only an assassination of the first rank would merit such a rehearsal.”

Howard nodded. “The President?”

“Possibly. Or a visiting head of state. Someone with protection, someone they can’t get close to. It wouldn’t be a gangland hit, they prefer to get in close with a shotgun or a handgun to the back of the neck. It has to be political. And it has to be soon. Your job, Cole, is to find out who the hit is, and to stop it. Do that and you’ll hopefully also catch the men who killed the Mitchell family. But that’s secondary, you understand? Your first priority is to put a stop to the assassination.”