The Viking Mission to Mars back in the 70s conducted remote tests on rocks there and did an isotope analysis. Some meteorites on Earth match up identically to them chemically. It is like a DNA match.
OK we have a decent correlation. Would not call it proof or even conclusive. IT is fun to speculate though.
I’m not sure if the NASA Viking mission did remote testing of Martian rocks. It may have only analyzed its atmosphere remotely and then matched it chemically to gases trapped within meteorites found on Earth.
“...unheralded measurement by the two NASA Viking spacecraft that landed on Mars in 1976. Although sent to conduct experiments to detect extant life in Martian soil (which they did not), the Viking landers gained redemption of sorts because the instruments measured the amounts of different gases in the thin Martian atmosphere. Those same gases were first found in 1983 by Donald Bogard and Pratt Johnson in very small amounts (but in the exact same proportions) trapped within shock glass veins and pockets in shergottite Elephant Moraine 79001, and now in at least five other Martian meteorites [on Earth].”
http://www.imca.cc/mars/martian-meteorites.htm
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From NASA:
“Why are they from Mars?
The 31 meteorites are unusual igneous meteorites (SNC achondrites named Shergotty, Nakhla, Chassigny are type examples). Most martian meteorites are 1.3 billion years old or less, much younger than typical igneous meteorites from asteroids which are 4.5 billion years old. They also have higher contents of volatiles than igneous meteorites. The conclusive evidence that the SNC meteorites originated on Mars comes from the measurement of gases trapped in one meteorite’s interior. The trapped gases match those that Viking measured in the martian atmosphere.”
http://curator.jsc.nasa.gov/antmet/marsmets/index.cfm