Yes they can be arrested, and extradited back to the State where the crime was committed. Simply leaving the State (or the country) does not end the criminal liability. Interstate (and International) extradition is actually very common, and for the type of offense you list, would be the type of case most States would follow through with an extradition request to get the person back in their courts. Good luck.
DISCLAIMER
I do not practice law in your State. This answer is provided solely for informational purposes only. This answer does not constitute legal advice, create an attorney-client relationship, or constitute attorney advertising.
Absolutely. Consider that the film director Roman Polanski was just arrested in another country for a case arising out of Los Angeles.
If the state wherein the crime took place investigated it, and determined that your friend was responsible, then they may have issued an arrest warrant for him. Such arrest warrants are usually entered into a national database for all law enforcement officers across the country to access.
He should seriously consider consulting with an attorney.
Disclaimer: This answer is provided solely for informational purposes only, and does not constitute legal advice or create an attorney-client relationship.
