A veteran of the U.S. Attorney’s Office in San Francisco has returned to federal government as the new chief of civil litigation.

Alex Tse, until recently a deputy city attorney for San Francisco, steps into the role long held by Joann Swanson, who retired September 28 after three decades in the U.S. Attorney’s Office.

Tse joined the city attorney’s office in 2007 and served as chief of neighborhood and resident safety. In 2010 he led a legal action to stop a guerilla marketing campaign on behalf of the online gaming company Zynga Inc. that left thousands of fake $25,000 bills glued to city sidewalks.

He previously spent 12 years as an Assistant U.S. Attorney and served as Swanson’s deputy from 2001 to 2006. After graduating from UC-Hastings law school, Tse worked as an associate at the firm then known as Thelen, Marrin, Johnson & Bridges and then at Sheppard, Mullin, Richter & Hampton.

U.S. Attorney Melinda Haag, who got to know Tse when both were line attorneys in the office, said she is “delighted” with his return.

“If I had to lose my civil chief, who has done such a tremendous job, I feel fortunate that Alex was available to come back,” Haag said.

Tse did not return a call seeking comment.

Ironically, a recent civil win for Swanson’s division came in litigation against Tse’s former office over postal delivery service to the city’s single-room-occupancy hotels.

The San Francisco city attorney’s office and tenants’ rights groups sued the postal service to require delivery to individual mailboxes in the hotels, which serve as residences to many poor and disabled people. A federal judge dismissed the action last year.

Haag called the Northern District of California a popular venue for claims against the federal government and said Tse’s caseload would be “interesting and varied.”

She added: “The Civil Division here doesn’t always get the attention that the Criminal Division does, but folks in our Civil Division do incredibly important work.”