Via the New York Times, this space science news:
...Perseverance had earlier found organic molecules — those with carbon and hydrogen atoms bonded together — in rocks on the crater floor of Jezero. But scientists were pretty sure those molecules had formed through non-biological processes.
The organics in the river delta rocks have the potential to tell a different story.
As Perseverance approached the river delta, the signal of organic molecules grew stronger, said Sunanda Sharma, a scientist working with an instrument on the rover that performs chemical analysis of the rock.
At Wildcat Ridge, “These signals were present at nearly every single point in every scan,” Dr. Sharma said. “They are also some of the brightest that we’ve seen thus far on the mission.”
Dr. Sharma said the data indicates the presence of ring-shaped carbon molecules known as aromatics, which the instrument is more sensitive at detecting. More complex organic molecules like proteins or amino acids would provide more compelling evidence of life, but that would have to await analysis after the sample is returned to Earth.
It's interesting to think about what kinds of molecules would be signs of life that would be left over after a very long time...