  GRB041219a is the brightest burst localised by INTEGRAL. The intense burst
occurred about ~250s after the precursor and the long delay enabled optical and
near infrared telescopes to observe the prompt emission. We present
comprehensive results of the temporal and spectral analyses, including line and
afterglow searches using the spectrometer, SPI, aboard INTEGRAL, BAT on Swift
and ASM on RXTE. We avail of multi-wavelength data to generate broadband
spectra of GRB041219a and afterglow. Spectra for the burst and sub-intervals
were fit by the Band model and also by the quasithermal model. The high
resolution Germanium spectrometer data were searched for emission and
absorption features and for gamma-ray afterglow. The overall burst and
sub-intervals are well fit by the Band model. The photon index below the break
energy shows a marked change after the quiescent time interval. In addition the
spectra are well described by a black body component with a power law. The
burst was detected by BAT and ASM during the long quiescent interval in SPI
indicating the central engine might not be dormant but that the emission occurs
in different bands. No significant emission or absorption features were found
and limits of 900 eV and 120 eV are set on the most significant features. No
gamma-ray afterglow was detected from the end of the prompt phase to ~12 hours
post-burst. Broadband spectra of the prompt emission were generated in 7 time
intervals using gamma-ray, x-ray, optical and near-infrared data and these were
compared to the high-redshift burst GRB050904. The optical and gamma-ray
emission are correlated in GRB041219a. The spectral lag was determined using
data from the BAT and it changes throughout the burst. A number of
pseudo-redshifts were evaluated and large dispersion in values was found.
