The given case would be handled by the Drug Enforcement Administration (DEA).
<u>Explanation:
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Department of Justice is an executive department at federal level in U.S. which deals with the administration of justice as well as the enforcement of the law in the country.
There are many federal agencies like Drug Enforcement Administration, criminal division, etc. working under the guidance of the DOJ for effective enforcement of law.
The case pertaining to investigation of ring of drug dealers is handled by the Drug Enforcement Administration (DEA) as it is leading federal agency working for the prevention of illegal distribution of narcotics in the country.
It undertakes the investigation and prosecution of the individuals as well as the gangs involved in the crimes relating to drug trafficking.
