I'm reading "Cold Case Christianity" and this paragraph stuck out.

In those days, as I was evaluating the claims of Christianity, I demanded a form of evidence (direct evidence) that simply isn’t available to anyone who is studying historical events. I failed to see that rejecting (or devaluing) circumstantial evidence would prevent me from understanding anything about history (when eyewitnesses of a particular event are unavailable for an interview). If I continued to reject (or devalue) circumstantial evidence, I would never have been able to successfully prosecute a single cold-case killer. All of us need to respect the power and nature of circumstantial evidence plays in making the case for Christianity.

The author had explained how circumstantial evidence compares to direct evidence, and how a solid case can be built on circumstantial evidence alone.

We don't have direct evidence today for Christianity - it is all historical, circumstantial, or subjective. But if a criminal case can be built on circumstantial evidence to convict the criminal, a circumstantial case can also be built to free the slave.

The atheist will claim that we cannot prove that God exists. True, we don't have direct evidence...but what does the circumstantial evidence point to?