In a surprise move, IG Boston isn't working on the expansion pack, but instead IG Australia, their counterparts in the southern hemisphere.

UPDATE: Thanks to readers of Computer Gaming World, we've learned some new details on the upcoming expansion pack. Some of them are very exciting for SWAT fans:

* Compliant, but unsecured suspects can no longer be considered secured. They will have to be secured, as was the case in SWAT 3.
* The expansion pack promises to offer missions which will be tied together by a linked storyline (a suspect is on the run across multiple missions).
* Simultaneous commands to both the red and blue teams is possible.
* Co-op missions for 10 players will now be supported.
* The quick mission maker can create scenarios which can be used in co-op.
* Voice-issued commands will now be more crucial.
* Suspects will now use blind supression fire.
* Evidence at a crime scene can be disposed of by suspects.
* A new multiplayer mode is planned which will feature "asymmetric" weapon distribution (think of Splinter Cell's multiplayer modes, perhaps?).