TULSA, Oklahoma - Homeland Security, along with many other agencies, served search warrants in six Tulsa neighborhoods Wednesday.

They were targeting a drug trafficking organization based in Mexico; six people were arrested and the agency recovered black tar heroin and more than $100,000.

The Department of Homeland Security is running the operation with the help of the Tulsa County Sheriff’s Office.

Wednesday, during the operation, ATF agents and the Tulsa County Sheriff's Office had to call in the bomb squad when they found a pipe bomb. Agents said it turned out to be harmless, with no explosive material inside.

The massive operation was designed to break up a drug smuggling operation that was moving heroin through Tulsa. Agents recovered three guns, two vehicles and 13 ounces of black tar heroin.

The search warrants were executed in six Tulsa neighborhoods - 25th and Memorial; Harvard and Pine; 41st and Peoria; 36th and Harvard; 15th and Denver; and near 12th and Lewis.

Agents arrested six people - five of them for drugs and guns; one had an outstanding misdemeanor warrant related to bogus checks.

This was a five-year long investigation called Operation Train Tracks, and agents said the raids made a huge impact on the heroin trade in Tulsa County.