In a not secured (!) article of ESA about methane on Mars it is suggested by an image of the Elysium Planitia region that methane has also been observed in that region where the Insight lander is.
The Heat Flow and Physical Properties Package is a science instrument onboard this lander that features a self-penetrating probe to determine how heat flows inside Mars.
Nicknamed "the mole" it trails a tether containing sensors to measure the temperature profile of the subsurface.
Question: Why has this unique opportunity not been used to detect methane in the subsurface behind the probe with semiconductor gas detectors or with some other type of methane detector using the shaft made by the probe ?