Four more Atlanta Department of Watershed Management employees have been charged with theft, the latest round of arrests in the city’s pledge to address internal widespread corruption.

The employees — Larry Tyler, Aaron Avery, Kenneth Carson and Antonio Denson — are accused of selling copper, brass and water meters to recycling centers since as far back as 2008, the Watershed department has confirmed.

All but Avery were arrested at a Watershed pipeyard facility off Peyton Road Monday afternoon. A warrant has been issued for Avery’s arrest. Three face felony theft charges. Carson has been charged with a misdemeanor.

In a statement, Mayor Kasim Reed said: “Unlawful activity will not be tolerated in my administration, and swift action will be taken to protect the taxpayers and residents of the city of Atlanta.”

Their arrests come roughly two months after two other Watershed employees were charged with theft.

Police say those employees, Charles Edwards and William Spalding, sold thousands of dollars of Watershed equipment to recycling centers since 2008. According to a police report, their arrests resulted from an investigation conducted by an employee of the City Auditor’s Office who tracked down receipts for the missing equipment.

At the time, Watershed Commissioner Jo Ann Macrina vowed additional arrests would follow.

Macrina said in a statement Monday that the department is making strides to crack down on theft by collaborating with the Atlanta Police Department and through new security measures.

Watershed has been under fire in recent years after city leaders discovered hundreds of thousands of dollars in missing or stolen equipment. The items include 28 industrial water meters weighing 700 pounds and worth $5,210 apiece, copper, pipes and more, according to police reports. City officials also have yet to find a missing backhoe worth $80,000.

The men arrested Monday are not believed to have been involved in those thefts.

City auditor Leslie Ward released a scathing report of the department’s inventory management practices last fall, an audit that found Watershed couldn’t account for more than 10,000 missing water meters. Ward’s office also found lax security at several Watershed facilities, including keys left in locks.

Macrina has said the bulk of the missing meters went unaccounted for between 2006 and 2009, long before Reed took office.

The department has worked to turn around its image by tightening its security measures, now requiring manager sign-off on equipment check-out, limiting who can order, receive and distribute equipment, and monitoring security-camera feeds from a central location. Watershed also will implement a bar-code system to track its equipment, worth a total of about $20 million.

Watershed has partnered with APD and Crime Stoppers Greater Atlanta to solicit information about wrongdoing within the department. They’re offering a reward of up to $10,000 for information that leads to an arrest and indictment.

Watershed isn't the only department under intense scrutiny. Four Department of Public Works employees were also arrested in March on similar charges.