spamassassin doesn't move spam to designated mailbox

[Chavdar Videff <chavdar@mr-bricolage.bg>]

Hi List,

We are using sendmail+procmail+spamassassin on Debian unstable.
Spamassassin is implemented sitewide.
Here is the procmailrc:

mail # cat /etc/procmailrc
DROPPRIVS=yes

#Mailing list start
:0:
* ^X-BeenThere: debian-user@lists.debian.org

:0:
* ^X-BeenThere: debian-firewall@lists.debian.org

:0:
* ^X-BeenThere: debian-isp@lists.debian.org

:0:
* ^X-BeenThere: debian-laptop@lists.debian.org

:0:
* ^X-BeenThere: <squid-users@squid-cache.org>
#Mailing list end

:0fw
| /usr/bin/spamc

:0:
* ^X-Spam-Status: Yes
spam_in_mail

However messages identified as spam do not go to /var/mail/spam_in_mail 
mailbox but are delivered to each user.

Here is the local.cf:
mail # cat /etc/mail/spamassassin/local.cf
# This is the right place to customize your installation of SpamAssassin.
#
# See 'perldoc Mail::SpamAssassin::Conf' for details of what can be
# tweaked.
#
###########################################################################
#
# rewrite_header Subject *****SPAM*****
# report_safe 1
# trusted_networks 212.17.35.
# lock_method flock

required_hits 8
rewrite_subject 1
report_header 1
use_terse_report 1
defang_mime 0
report_safe 0
use_bayes 1
auto_learn 1

What is wrong? We followed the instructions in 
http://www.stearns.org/doc/spamassassin-setup.current.html#sitewide

There are no .procmailrc in home directories of the users.

Regards
Chavdar Videff