template loop is accessing all posts content?

In a custom theme, I have several page templates on which I want one category only to appear. The posts appear as they should, all contain lists of documents. However today I just discovered that when there is a link to a document that is broken, the page reloads but with *ALL* the posts’ content displayed. I can’t show you a link the site is password-protected.

I think I have made a mistake with the loop but cannot figure this out.
The template is named page-projects.php.

<div id="content">

<?php query_posts('cat=4'); ?>

<?php if(have_posts()) : ?>

<?php while ( have_posts() ) : the_post() ?>
		<div id="post-<?php the_ID() ?>" class="documents">
			<h2 class="postTitle"><?php the_title() ?></h2>
				<div class="postContent">

				<?php the_content(); ?>

				</div><!-- .postContent -->

		</div><!-- .post -->

<?php endwhile ?>

		<div class="navigation">
			<div class="alignleft"><?php next_posts_link('&laquo; Older Entries') ?></div>
			<div class="alignright"><?php previous_posts_link('Newer Entries &raquo;') ?></div>
		</div>

<?php endif ?>

</div><!-- #content -->