Cooey shrugged. "I don't know. But he's pretty good, and he's quick. He's using a three-pronged approach to get past our defences. He starts by trying simple permutations of names of known users, then tries names from our own Dictionary and finally a list of four hundred and thirty-two passwords." As he said this, the Jesuit twisted his mouth slightly, as if suppressing a smile. "Now he's probing the entrances to INMA VAT."

Father Arregui drummed his fingers anxiously on one of the computer manuals littering the table. INMA VA T was a confidential list of the high-ranking members of the Roman Curia. Access was possible only with a secret personal code.

"Signal tracker?" he suggested.

Cooey jerked his chin towards the monitor at the neighbouring table, as if to say, "I've already thought of that". Connected to the police and to the Vatican's telephone network, the system recorded all information on an intruder's signal. It even contained a trap, a series of paths that slowed intruders long enough for them to be located and identified.

"This won't get us very far," said Cooey after a few moments. "Vespers has hidden his entry point by jumping between different telephone networks. Every time he makes a loop through one of them, we have to trace him right back to the exchange. He'd have to be here a long time before we could do anything about him. And he'd still be able to do some damage, if that's what he wants."

"What else could he want?"

"I don't know," the younger man answered, looking both intrigued and amused. He went on, his face serious again. "Sometimes they just want to have a look around, or leave a message – 'Captain Zap was here', that kind of thing." He paused, watching the screen. "But this one's going to a lot of trouble just for a saunter around the system."