How can I understand a word "suspect" , even either to guess or to doubt in a certain sentence

Question

Scientists would be more likely to suspect that Mars once held life if there were evidence ...

I thought that if there were certain evidence, the scientists would NOT be going to believe that Mars once held life. Because, I thought that the word "suspect" means to doubt.

But the answer was the opposite. The word "suspect" means to feel, so the sentence states that if there were certain evidence, the scientists would be going to believe that Mars once held life.

How I understand this situation. In the dictionary, the word suspect has both meanings.

Answer 1

To suspect can mean:

to think or believe something to be true or probable:
From seeing the cloudy sky, I suspect it will rain soon.

to think that someone has committed a crime or done something wrong:
A woman has been found dead. Police suspect her husband of murder.

to not trust; to doubt:
I suspected him when I found out he had been lying.

Suspect (Cambridge Dictionary)

In order to know which meaning is intended in any particular context, (1) be aware of these meanings (2) carefully consider the context.

In this case, scientists would be more likely (positive) to suspect a positive thing (first meaning above) (that, yes, there once was life on Mars) if there were evidence (such as methane depleted in the Carbon-13 isotope). Common sense tells us that Mars is not a suspect in a criminal case. Also, if a negative doubt were being described, the sentence would contain negative words, e.g. scientists would be less likely (negative) to suspect that there had been life on Mars if there were no evidence (negative) of... (etc).