“Why the fuck is that guy singing? Can’t someone shut him up?,” Marie Colvin whispered urgently after dropping into the long, dark, dank tunnel that would lead her to the last reporting assignment of her life. It was the night of February 20, 2012. All Colvin could hear was the piercing sound made by the Free Syrian Army commander accompanying her and the photographer Paul Conroy: “Allahu Akbar. Allahu Akbar.” The song, which permeated the two-and-a-half-mile abandoned storm drain that ran under the Syrian city of Homs, was both a prayer (God is great) and a celebration. The singer was jubilant that the Sunday Times of London’s renowned war correspondent Marie Colvin was there. But his voice unnerved Colvin. “Paul, do something!” she demanded. “Make him stop!”

For anyone who knew her, Colvin’s voice was unmistakable. All of her years in London had not subdued her American whiskey tone. Just as memorable was the cascade of laughter that always erupted when there seemed to be no way out. It was not heard that night as she and Conroy made their way back into a massacre being waged by the troops of President Bashar al-Assad near Syria’s western border. The ancient city of Homs was now a bloodbath.

“Can’t talk about the way in, it is the artery for the city and I promised to reveal no details,” Colvin had e-mailed her editor after she and Conroy made their first trip into Homs, three days earlier. They had arrived late Thursday night, 36 hours away from press deadline, and Colvin knew that the foreign desk in London would soon be bonkers. The day before she walked into the apartment building in Homs where two grimy rooms were set up as a temporary media center, the top floor had been sheared off by rockets. Many thought the attack had been deliberate. The smell of death assaulted Colvin as mutilated bodies were rushed out to a makeshift clinic blocks away.

At 7:40 a.m., Colvin had opened her laptop and e-mailed her editor. There wasn’t a hint of panic or apprehension in her exuberant tone: “No other Brits here. Have heard that Spencer and Chulov of the Torygraph [Private Eye’s nickname for the Telegraph] and Guardian trying to make it here but so far we have leap-frogged ahead of them. Heavy shelling this morning.”

She was in full command of her journalistic powers; the turbulence of her London life had been left behind. Homs, Colvin wrote a few hours later, was “the symbol of the revolt, a ghost town, echoing with the sound of shelling and crack of sniper fire, the odd car careening down a street at speed Hope to get to a conference hall basement where 300 women and children living in the cold and dark. Candles, one baby born this week without medical care, little food.” In a field clinic, she later observed plasma bags suspended from wooden coat hangers. The only doctor was a veterinarian.

Now, on her way back into Homs, Colvin moved slowly, crouching down in the four-and-a-half-foot-high tunnel. Fifty-six years old, she wore her signature—a black patch over her left eye, lost to a grenade in Sri Lanka in 2001. Every 20 minutes or so, the sound of an approaching motorcycle made her and Con­roy flatten themselves against the wall. Conroy could see injured Syrians strap­ped on the backs of the vehicles. He worried about Colvin’s vision and her balance; she had recently recovered from back surgery. “Of all the trips we had done together, this one was complete insanity,” Conroy told me.