Night Victims (The Night Spider) by John Lutz

he stared pensively at the window for a while longer before closing it.
    “No marks on the marble sill,” he said. “Maybe a slight scuff mark from the killer’s shoe. But we can’t be sure.”
    Paula said nothing. She wasn’t sure of anything yet in this case.
    “Nothing for sure on the windowsills at the other two crime scenes, either,” Horn said.
    He walked back into the living room, and Paula followed.
    “You reinterview the neighbors here?” he asked Bicker-staff.
    “We just finished up before you got here. There were a few slight discrepancies, but their stories are pretty much consistent with their first interviews. Basically, nobody saw or heard anything unusual.”
    “We were about to leave when you arrived,” Paula said.
    “I’ll leave with you,” Horn said. “After we get done on the roof, we’ll find someplace to eat supper and compare notes.”
    “Roof?” Paula said.
    Horn nodded. “Yeah. You know—the windowsills.”
    “But they were left mostly unmarked when the killer climbed in.”
    “And out,” Bickerstaff added. “The techs found nothing even microscopic that was of use on the windowsills.”
    “Like a microscopic dog that didn’t bark in the night,” Horn said.
    Paula grinned. “Sherlock Holmes.”
    “I’d have guessed Lassie,” Bickerstaff said.
    “Got a handkerchief in your purse?” Horn asked Paula.
    She searched but couldn’t find one. “Only tissues.” Among other items she pulled from her purse while rummaging through it was a white latex glove of the sort used to examine crime scenes.
    “That glove’ll do,” Horn said.
    Paula and Bickerstaff glanced at each other.
    They followed Horn into the bedroom, where he got a wire hanger from the closet, straightened it, and tied the white glove on one end. He then went to the window and opened and closed it, wedging the hanger between frame and sill so the end with the glove stuck outside about eighteen inches.
    “Oughta do,” he said.
    Understanding now, Paula led the way out of the apartment. She was starting to like this, Horn thinking a little outside the box. Sometimes a little was all it took. Outside was outside.
    She could hardly wait to get to the roof.
     
    As soon as they were on the roof, Bickerstaff wedged a piece of tile in the service door so it wouldn’t close and trap them up there. Then they went to the low brick parapet at the roof ‘s edge, approximately above the window to Sally Bridge’s bedroom. About ten feet from the parapet, Horn held out a hand and stopped them. “Look at the tar and gravel near the edge,” he said. “It seems it might have been disturbed.”
    Paula looked. The gravel adhered to the blacktop roof seemed to have been rearranged recently, some of it even kicked or scraped loose.
    Horn went to the parapet and examined it, then leaned over it, staring straight down.
    “I see the glove sticking out right under the disturbed gravel,” he said, turning away and standing up straight. And there’s a spot on the parapet where the tile’s been rubbed clean. And look at this.”
    Paula and Bickerstaff moved closer to see where he was pointing. There was what appeared to be a fresh hole low in the brickwork of the parapet, as if something sharp had been driven into the brick and mortar at an angle.
    “A whatchamacallit, maybe,” Bickerstaff said. “One of those steel spikes mountain climbers use to fasten ropes to cliff faces.”
    “A piton,” Horn said. He glanced around, then walked over to where a grouping of vent pipes protruded from the roof.
    He stooped down next to one. “Look at the way the grime has been rubbed away from the base of this pipe. My guess is our killer drove in his piton near the roof ‘s edge, then ran the roof end of the rope back to this vent pipe. He then wrapped it around the pipe as a safety precaution in case the piton broke free when he draped the other end of the rope down the building wall and began his descent.”
    Paula stared at the