Please, help me on this. I would like to know if this is a crime? what is the penalty in MD? to what kind of law does it belong? How serious is it if you receive a summon for it?

If you are wondering if buying alcohol with a fake ID is a crime, OF COURSE it is! It is not an overly severe crime, but a crime nonetheless.

MD 10-113 Misrepresentation of Age
MD 10-114 Minor in possession
MD 10-115 False identification of Age

All are citable offense with $500 fines for first offense, $1000 for second.

If the fake ID is a completely ficticious ID then MD 8-303 may apply. It is a misdemeanor with max 6 months in jail and/or $500 fine.

Yes it is illegal. Have you browsed through the information in LawInfo's Free Legal Resource Center to learn more about your issue yet? See: http://www.lawinfo.com/consumer.html and http://resources.lawinfo.com/en/index.html. You can certainly try to speak to a lawyer to determine what legal options may be available. In the meantime, you may be able to learn more on your own. Search the "Free Legal Resources" tab, or browse the Consumer Resources. Good luck.