  We analyzed data obtained by the SPI telescope onboard the INTEGRAL
observatory to search for short transient events with a duration from 1 ms to a
few tens of seconds. An algorithm for identifying gamma-ray events against the
background of a large number of charged particle interactions with the detector
has been developed. The classification of events was made. Apart from the
events associated with cosmic gamma-ray bursts (GRBs) confirmed by other space
experiments and the activity of known soft gamma repeaters (for example, SGR
1806-20), previously unreported GRBs have been found. GRB candidates and short
gamma-ray events probably associated with the activity of known SGRs and AXPs
have been selected. The spectral evolution of 28 bright GRBs from the catalog
has been studied extensively. A new method for investigating the spectral
evolution is proposed. The energy dependence of the spectral lag for bursts
with a simple structure of their light curves and for individual pulses of
multipulse events is shown to be described by a logarithmic function, lag ~
A*log(E). It has been established that the parameter A depends on the pulse
duration, with the dependence being universal for all of the investigated GRBs.
No negative spectral lags have been detected for bursts with a simple structure
of their light curves.
