If an unknown substance found on a meteorite contains no trace of carbon can scientist conclude that there is life at the meteorite origin?

The scientists rely on the following cues to hypothesise and test for the presence of life on various extraterrestrial bodies:

1. Presence of water

2. Presence of hydrocarbons

3. Presence of carbon

4. Presence of salt pans  

The presence of hydrocarbons may indicate that there's anaerobic life thriving beneath the surface of the meteorite. The presence of traces of carbon may indicate that there was life once thriving on its surface ( which however is not possible in case of a meteorite because of its size). The absence of any of the above listed items will indicate that the surface of the meteorite is devoid of any life.