Mercer removed a large black object from the bag and dangled it in front of us.

“Yeah,” Billy said. “That’s what the fireman had on his face.”

“Found it halfway up the block,” the sergeant said. “Right in the perp’s flight path.”

“That’s not department gear,” Mike said. “It’s a gas mask. Military style.”

It was a black rubber helmet, with two holes for the eyes, and a broad snoutlike respirator that would fit over the mouth, with a long hose attached.

“Couldn’t see a damn thing,” Billy said. “It covered his entire face.”

“What did the cops do?” Mike asked.

“I led them down to the basement. They knocked on Tina’s door and one of them identified himself, said they were police. That’s when she started yelling at them to leave her alone. I mean screaming at them. Freaked out. Sounded like she collapsed-maybe fell onto the floor-crying the whole time.”

“What makes you think she’s alone in there?”

“We’re guessing,” Mercer said. “She’s the only one to make a sound-no scuffling, no struggling, no other voices. But that’s another reason ESU won’t leave.”

Mike prodded my side with his fingers as we started up the front steps. I went back in the vestibule toward the basement staircase.

“One of the cops told Tina he just wanted to make sure that the fire hadn’t affected her,” Billy said, drawing a handkerchief from his pocket to wipe his smoke-fogged glasses. “Asked her if she could stand up and look through the peephole at his badge, for identification. She went wild.”

“What do you mean?” Mike asked.

“Tina screamed at the cop. Told him that’s how the guy got in. The fireman. That he showed her his badge and she opened the door.”

“It was the fireman who was inside her apartment? You knew, Coop?”