Seven people were arrested and 89 pounds of white heroin were seized in Tucson as part of a DEA 11-month investigation, authorities said Tuesday.

The investigation, "Operation Smack Talk, "targeted a large-scale Mexican heroin trafficking organization responsible for distributing hundreds of pounds of heroin from Tucson to various cities on the west coast," according to a Drug Enforcement Administration news release.

The names of those arrested and facing trafficking charges were not released. The seven suspects remain in federal custody. The investigation is continuing. 

On June 13, federal agents and Tucson Police Department officers executed a federal search on a suspected stash house, and found heroin inside a bedroom closet, according to the release. The address of the stash house was not released.

The organization smuggled the heroin into Arizona from Mexico using several vehicles with built-in hidden compartments, and then the heroin was taken to a house in the Tucson-area, states the release.

During the investigation, DEA agents seized a total of 123 pounds of high-grade heroin with an estimated street value of more than $7.5 million. Seven vehicles and $300,000 in drug proceeds also were seized, according to the release.

In addition to DEA and the Tucson Police Department, Homeland Security Investigations and the Marana Police Department took part in the investigation.