NEWARK, N.J. (AP) — New Jersey contractors hired to replace lead water pipes in the state’s largest city left lines in the ground and then fraudulently collected payment for work they didn’t do, federal prosecutors said.

Michael Sawyer, 57, of Burlington, New Jersey, and Latronia Sanders, 55, of Roselle, New Jersey, were arrested Thursday and charged with conspiracy to commit wire fraud, according to the U.S. Attorney for New Jersey Philip Sellinger.

Newark, like other cities across the country, struggled for years with replacing its aging lead service lines. In recent years, officials announced it had replaced more than 20,000 lines.

Sawyer served as president and CEO of JAS, which calls itself a construction land development firm, while Sanders worked as a foreperson on the company’s crews hired in a $10 million contract with the city to replace lead lines.

The pair did not replace all the pipes they were hired to, according to authorities, but still submitted applications for payment. They included false documents like photographs purporting to show the replacement was done or not needed.

Email and phone messages left Friday with JAS have not been returned. Attorneys for Sawyer and Sanders were not listed in online court records.

In a joint statement, Newark Mayor Ras Baraka and Department of Environmental Protection Commissioner Shawn LaTourette said officials learned in January that some lines might not have been replaced as expected. That led to a randomized audit of some 400 pipes. Of those, 33 properties were found to contain some remaining lead. They’ve been replaced, the officials said.

“At this time, there is no need for Newark residents to take any additional precautions with respect to their drinking water,” the statement said.