D.C. Police Chief Cathy Lanier said the bust stopped a new drug organization with connections to Mexico from establishing itself in the District.
"We see all the violence with the drug trade in Mexico. The last thing we want is to have it here," Lanier said.
Arrested last week were Gezo G. Edwards, 37, of Silver Spring; William M. Bowman, 31, of Bowie; Robert C. Richards, 35, of Seat Pleasant; and Willie S. Moorer, 37, of D.C. They are being held without bond awaiting trial.
The investigation began last year with a tip obtained during a large drug bust at the Potomac Gardens housing complex in Southeast Washington, according to a law enforcement officer who asked not to be named.
With that piece of intelligence, undercover police officers made several small purchases of cocaine, enough to obtain a wiretap, the source said.
FBI agents listened in on phone conversations as the suspects discussed who was supplying the drugs and where the crew was stashing it, the source said.
The investigators learned that the drugs were going to be secured at a self-storage unit at 3005 Kenilworth Ave. in Hyattsville, and obtained another federal warrant to observe the storage facility via closed-circuit television.
Last week, FBI agents watched as Edwards and Bowman wheeled a black suitcase into the self-storage Unit A306, charging documents said. The men opened the case and counted out kilo quantities of a white substance, then begin to break down the powder into small quantities.
When the men left, FBI agents obtained an emergency warrant to search the storage locker and seized 30 kilograms of cocaine, a semiautomatic pistol and a Bushmaster AR-15 assault rifle. Then the authorities waited.
The next morning, Bowman returned. He opened the door, saw that the contraband had vanished, and immediately called his bosses, the source said.
Richards, Moorer and Edwards raced to the storage facility, where authorities rounded them up.
Authorities also seized $550,000 in cash, luxury cars and two more weapons, Lanier said.
Staff Writer Freeman Klopott contributed to this report.