  We present millimetre and NIR molecular-line observations of the Tornado
nebula and its Eye. The observations were motivated by the presence of OH(1720
MHz) maser emission towards the nebula, believed to be an indicator of
interaction between a supernova remnant and a molecular cloud. We found that
the distribution of molecular gas around the Tornado complements its radio
morphology, implying that the nebula's appearance has been influenced by the
structure of the surrounding molecular gas. Our NIR H$_2$ observations revealed
the presence of shocked molecular gas at the location where the nebula is
expanding into the surrounding molecular cloud.
  It has been suggested that the Eye of the Tornado is related to the nebula on
the basis of their apparent proximity. Our NIR and millimetre-line observations
show that the two objects are not spatially related. Br $\gamma$ line emission,
in conjuction with IR data at longer wavelengths and high-resolution radio
continuum observations, suggests that the Eye is a massive protostellar source
deeply embedded within a dense molecular core.

Astrophysics