DPS trooper obtains reasonable suspicion to make a traffic stop in Cherokee County (expired license plate) but is unable to make a traffic stop before travelling approximately 100 yards into Smith County. Driver is found to be in possession of marijuana. Can we prosecute in Cherokee County? My initial thought is "yes," since the marijuana was travelling with him?

The answer is indeed yes. Article 13.04 CCP specifically provides a 400 yard leeway. But you may want to be careful in how you word the indictment/information to specifically cite the wording in 13.04. i.e. "in Cherokee County or within 400 yards of the border of Cherokee County."

Also, remember that venue is not an element and the standard of proof is preponderance of the evidence, not beyond a reasonable doubt.

I would not put the 400 yards of county line language in the indictment, but just say it was in Cherokee County. Proving the stop was within 400 yards of the county line is another thing you have to prove, and it may prove to be more complicated that it seems at first blush.

If the trooper observed the def. drive from Cherokee Co. into Smith Co. and then found marij. in the vehicle while it was in Smith County, the marij. had to have been in the car while it was traveling in Cherokee County. That's just common sense.