Code to Zero Page 0,46

with a chalk stripe."

He turned to the detective. 'So, you can put out a photo and description including the clothes he's wearing.'

You think he's still in town.'

Yes.' Anthony was not as sure as he pretended, but he could not think of any reason for Luke to leave Washington.

'I presume he's in a car.'

'Let's find out' Anthony turned to Mrs Bonetti. 'What's the name of the white-haired lady who lives across the street, a couple of doors down?'

'Rosemary Sims.'

'She spends a lot of time looking out her window?'

'We call her Nosy Rosie.'

'Excellent.' He turned to the detective. 'Shall we have a word with her?'

Yep.'

They crossed the street and knocked on Mrs Sims's door. She opened it instantly - she had been waiting in the hall. 'I saw him!' she said immediately. 'He went in there looking like a bum, and came out dressed to the nines!'

Anthony made a gesture indicating that Hite should ask the questions. Hite said: 'Did he have a car, Mrs Sims?'

'Yes, a nice little blue-and-white model. I thought it didn't belong to anyone in this street.' She looked at them slyly. 'I know what you're going to ask me next.'

'Did you happen to notice the licence plate?' Hite asked.

Yes,' she said triumphantly. 'I wrote it down."

Anthony smiled.

3 P.M.

The upper stages of the missile art contained in an aluminium tub with a cast magnesium base. The upper-stage tub rests on bearings, allowing it to spin during flight. 'It will rotate at about 550 revolutions per minute to improve accuracy.

On 37th Street at the end of O Street, the iron gates of Georgetown University stood open. Around three sides of a muddy lawn were Gothic buildings of rusticated grey stone, and students and faculty hurried from one building to another in their cold-weather coats. As Luke drove slowly in, he imagined that someone might catch his eye, recognize him, and say. 'Hey, Luke! Over here!' And the nightmare would be over. '

Many of the professors wore clerical collars, and Luke realized this must be a Catholic university. It also appeared to be all-male.

He wondered whether he was Catholic.

He parked in front of the main entrance, a triple-arched portico marked 'Healy Hall'. Inside he found a reception desk and the first woman he had seen here. She said that the physics department was directly below where he stood, and told him to go outside and turn down a flight of steps that led beneath the portico. He felt he was coming nearer to the heart of the mystery, like, a treasure hunter penetrating the chambers in an Egyptian pyramid.

Following her directions, he found a large laboratory with benches down the centre and doors on either side that led to smaller offices. At one of the benches, a group of men were working with the components of a microwave spectrograph. They all wore eyeglasses. Judging by their ages, Luke thought they were professors and graduate students. Some of them might easily be people he knew. He approached them with an .expectant look.

One of the older men caught his eye, but there was no flash of recognition. 'Can I help you?'

'I hope so,' Luke said. 'Is there a department of geophysics here?'

'Goodness, no,' he said. 'At this university, even physics is considered a minor subject' The others laughed.

Luke gave them all a chance to look at him, but none seemed, to know him. He had chosen badly, he thought despondently; he probably should have gone to George Washington University. 'What about astronomy?'

'Why, yes, of course. The heavens, we study. Our observatory is famous.'

His spirits lifted.'Where is it?'

The man pointed to a door at the back of the lab. 'Go to the other end of this building and you'll see it on the far side of the baseball diamond.' He returned his attention to the bench.

Luke followed a long, dark, dirty corridor that ran the length of the building. Seeing a stooped man in professorial tweeds coming the other way, Luke looked him in the eye, a smile ready to break out if the professor recognized him. But a nervous expression came over the man's face and he hurried by.

Undaunted, Luke walked on, giving the same look to everyone he passed who might possibly be a scientist; but no one showed any sign of recognition. Leaving the building, he saw tennis courts and a view of the Potomac river and, to the west across the sports field, a white dome.

He approached it with mounting anticipation. On the flat roof of a small two-storey