07:35 A.M. EST

Pittsburgh is a city of brutally steep hills, so it was only when Greg crested the top of Joseph Avenue, the wipers of his Mini Cooper swishing against the sleet, that he realized something was wrong. The road plunged steeply in front of him before leveling out in front of the school. Down below, where teachers and the earliest of parents should be maneuvering for parking spaces, the road was blocked by a couple of police cruisers, hulking SUVs in the black and gold of the Pittsburgh PD, blue beacons spinning ominously in the fading dark.

He hung a quick left, going the wrong way down a one-way street barely wide enough for his tiny car, and turned right onto Dean Close, a two-block access road that ran along the back of the school, separating the redbrick majesty of the Calderhill Academy main building from the artificial turf of the sports ground.

Dean Close, too, was blocked. More police cruisers. But also luminous yellow tape and the huddled, hard-bitten figures of law enforcement. Greg swore softly, pulled up short of the closest police cruiser and parked against the edge of the playing field. He had barely unclipped his seatbelt when he was approached by a uniformed officer wielding a flashlight.

‘You can’t park here,’ he said, brusque, but not unfriendly. ‘You need to turn around.’

‘Sure. What’s going on here?’

‘Can’t say. Turn around.’

Greg tuned out a small upwelling of irritation and did what he was told. With Joseph blocked off, the nearest free parking was on a side street two hundred yards distant. Returning to Joseph as a pedestrian, no one stopped him walking past the road-blocking cruisers. He skipped hurriedly up the front steps and entered the building. Faculty were standing in the main lobby, talking together in tight, huddled knots. A police officer stood at the top of the stairs that led down to the basement, barring the way.

‘Good morning, Mr Abimbola.’

It was Stacey, the security lady, eyes wide and anxious.

‘Good morning. What in God’s name is going on? Has some arsehole threatened to blow up the school?’

‘They’ve found a body in the basement,’ Stacey said. She was shaking, her hands clasped to her shoulders. ‘Someone’s been killed.’

Something like the old excitement stirred in his chest. His heart rate picked up, analysis kicked in: threats, escape routes … and the need for appropriate reactions. His face molded itself into a decent facsimile of shock.

‘Who?’ he asked, forcing his voice to rise.

‘Ms Delcade. Vern Szymanksi found her. Says someone musta dragged her down there and stabbed her to death.’