The Haunted Bones by PM Weldon

"I touched cold brick behind it. Or cinder block—if this
is a firewall."
    "We should punch that out to see." She
started to reach through the shelf frame but her arm wasn't long
enough.
    I pulled her back. "This isn't a legitimate
crime scene and it's owned by the bank. We can't go destroying
property without permission. And this place has an interested
buyer. We're just here to observe."
    She gave me a disgusted look. "Jim never
said you were a stickler for the rules."
    "Well, that's because I used to not be." I
helped her up, and we stood and faced the shelves. "He was always
the one to rein me in." Except that night when he ran into that
warehouse. "But why?"
    "Why what?"
    Oh crap. I said that with my outside voice.
"I was thinking of Jim that night at the warehouse. I remember
getting there after him and he was already…dead. But what I don't
know is why. He was such a damn asshole about following the rules,
and he knew in a hostage situation we were supposed to wait for
backup. If he knew Llse had been taken, then he would have called
and waited. But he didn't."
    She was watching me intently, her eyes wide.
"You remember anything else?"
    "Not yet." I moved over to
look at the antique mirror. "But I think I will. Eventually. Jimmy
always looked at the why when we worked a case. Motive was his big thing
because without motive, it never makes sense. And it has to make
sense."
    "I don't think murder ever makes sense."
    "It does." I reached out to touch the
mirror. "Let's take this case—this Birch guy killing his wife, the
girl next door, and himself. We've already seen by looking at the
photos that the way it was written up can't be the way it happened,
and it didn't make sense. Why kill them? Two defenseless women? The
ferocity used to kill the two of them is usually only present in a
crime of passion. This guy was angry. I mean, he was pissed off." I
looked at her. "Why? I can't find any motive in the files. No
infidelity, no mention of tax evasion, no embezzlement. Why kill
these two women?"
    Jewels lifted her shoulders in a shrug.
"Like I said, it doesn't always make sense."
    "It makes sense if you put a fourth person
in. Someone else who was mad and took it out on them. If it was
Cahan, the only reason I can come up with is he discovered
something. Something his daughter did."
    She put her hand on my arm. "His daughter
was seeing Mr. Birch!"
    "Maybe." I redirected my attention back to
the mirror. It was loose and moved a small bit back and forth. Six
tiny screws held it in place against dry wall. I reached up and
twisted one of the arms to the side, then methodically, with my
other hand bracing the mirror, moved all of them. The mirror came
forward in my hands so I lifted it out and set it carefully on the
bar.
    "Holy hell."
    I turned to see a shit-load of black mold on
the wall behind it. But what had Jewels's eye and mine was a
plastic bag smashed against the corroded drywall. "Let me get
pictures of this with you standing there. We need to do this by the
book, okay?"
    I grabbed my tablet.
    Jewels frowned at me. "You're gonna take
shots with that?"
    "Yeah. I don't want to go and look for my
camera, and I didn't really prepare to do this." I held the device
up so I could actually record her lifting the bag out of the
drywall. "Is that…is that a hole?"
    She nodded, stuck her gloved hand into it,
and patted something. "Sure is. And guess what…this is brick back
here, not cinder block. This wall's out of code."
    Brick? I knew what the two materials felt
like, and I had touched cinder block under the bar.
    Jewels pulled her penlight out and shined it
inside. "There's a hole on the other side as well."
    "You mean to the adjoining store?"
    "Looks like it."
    I continued to record as she placed the bag
on the bar and pulled the contents out. It was a diary of some
sort, and a collection of letters and notes stuffed in the back. I
recognized the type of diary because I'd bought Pink of one of them
a few years back