https://www.cnet.com/news/science-finally-confirms-that-mars-is-farting/

A paper published in Nature Geoscience on Monday lays out the detection of methane near Gale Crater on the surface of Mars on June 16, 2013, using instruments on the Mars Express orbiter. What's important about that date is that NASA's Curiosity rover detected methane at Gale Crater a day earlier. 

"This finding provides independent confirmation of debated measurements obtained by the Curiosity rover one day earlier," reads a release.