IIRC, the conclusion that it was proof of martian life was undercut by fairly reliable evidence showing that the patters could have been created here on earth. There has been no persuasive rebuttal to this criticism from the discoverers, although the case is not closed either.
This is something like the water on the moon phenomenon. The evidence fails because earthly causes cant be ruled out.
For those who wish to maintain an illusion, ignorance is the best source of knowledge.
It's referred to as the ALH84001 meteorite (ALH indicates it was found by Allan Hills). It was found in 1984, but the estimates are that it landed on Earth roughly 13,000 years ago - that's a long time for Earthly contamination. I found an article in 2007 that said the meteorite had been analyzed by the Carnegie Institution's Geophysical Laboratory. That might qualify for "who studied it last".
The study theorized that the organic compounds found on the meteor were created on Mars by chemical reactions within the rock rather than via Martian life forms, either when the rock was first formed (during volcanic activity) or during the rock's impact ejection from Mars.
'How shall a man judge what to do in such times?' 'As he ever has judged,' said Aragorn. 'Good and ill have not changed since yesteryear; nor are they one thing among Elves and Dwarves, and another among Men. It is a man's part to discern them, as much in the Golden Wood as in his own house.'