  Earlier classification analyses found three types of gamma-ray bursts (short,
long and intermediate in duration) in the BATSE sample. Recent works have shown
that these three groups are also present in the RHESSI and the BeppoSAX
databases. The duration distribution analysis of the bursts observed by the
Swift satellite also favors the three-component model. In this paper, we extend
the analysis of the Swift data with spectral information. We show, using the
spectral hardness and the duration simultaneously, that the maximum likelihood
method favors the three-component against the two-component model. The
likelihood also shows that a fourth component is not needed.
