That's the claim made by some scientists from Sri Lanka and Wales on material from a witnessed fall, based on elemental content and electron microscopy of structures inside the rock. The problem with these claims is always a) ruling out contamination (the fragments landed in rice paddies) and b) making a claim of life based on electron micrographs.
My question: why do these claims never rely on gas chromatograph or NMR data (for instance)? No, we wouldn't necessarily know what we're looking for, but you'd very likely see some large complex molecules, a few of them much more common than others, and then we wouldn't have another 1996 Martian meteorite false-start. Until then any discussion of space algae is premature. And I even think there will actually be evidence of life (panspermia or von Neumann probes) on asteroids and comets - I just don't think this is evidence thereof.