Fifteen years ago, a team of NASA scientists announced they thought they'd found evidence for life on Mars in a meteorite that had originated on the Red Planet. The science community generallly never bought that conclusion, but the team has not backed away from it.
Various studies have since shown that all the features the NASA team points to as evidence of life could be produced non-biologically, The science consensus is, therefore, that we should assume they were produced non-biologically unless or until we have powerful additional evidenc to the contrary. Scientists generally don't want to declare they've found alien life only to be proven wrong. It's a good, solid, conservative position. Whether it leads to the correct answer or not is yet to be determined.