A person has committed crime & is being prosecuted in the criminal court of law. He wants toleave the country & I want to know his passport no. to stop him leaving this country.

A person has committed crime & is being prosecuted in the criminal court of law. He wants to leave the country & I want to know his passport no. to stop him leaving this country.

If a person has already left the country & the criminal case is pending against him, can we bring him back to the country & how?

As a private citizen this information would be meaningless to you as you cannot stop them leaving the country.
This is an issue for the courts and police.

As a private citizen this information would be meaningless to you as you cannot stop them leaving the country.
This is an issue for the courts and police.

Can we apply to the passport office with the copy of the criminal case filed against him to seize his passport?

This is an issue for the courts and police, NOT a private citizen!

The criminal is lying in the court that he does not have the passport, but I know that he had already travelled before to other countries, in that case, how can we prove to the court that he has the passport?

If the criminal case is pending, can the regional passport office not seize the passport of the person against whom the case is pending?

All you can do is ask the DA to make a motion to the judge to order him to turn in his passport.

Depending on the flight risk of the person, they may or may not do this.
Since the person is merely being tried, they are not convicted it does not mean they can not travel for variouis reasons as long as they are back for court.

And you don't prove to the court he has the passport, the court ( DA) may find out by looking if they want to.

You as a private citizen have no say in this, other than asking the DA to do something.