LITTLE ROCK — Arkansas State Treasurer Dennis Milligan said Monday his chief of staff, Jim Harris, is retiring after having served in that office since Milligan took office in January 2015.

The announcement comes less than a month before Harris and Milligan are scheduled to appear as defendants in a civil trial in a federal defamation and discrimination lawsuit filed by Milligan’s former outreach manager, David Singer.

An earlier attempt to try the case ended Aug. 12 when U.S. District Judge Brian Miller declared a mistrial after Harris suffered a health problem in the courtroom and was carried out by paramedics. Singer’s attorneys argued that jurors would be prejudiced by sympathy for Harris.

Harris cited his health as the reason for his retirement in a statement Monday.

“It has been an honor to serve the people of Arkansas and I am grateful for the opportunity Treasurer Milligan afforded me. However, at this time it is best that I focus on my health. I look forward to seeing the continued success of Treasurer Milligan and his office,” Harris said.

A former editor and reporter for the Texarkana Gazette, Harris served as then-Gov. Mike Huckabee’s director of press operations from 1996-2006, as bio-terrorism and agriculture coordinator for the Arkansas Department of Emergency Management from 2006-07 and as Milligan’s chief of staff while Milligan was Saline County circuit clerk from 2011 until the end of 2014.

Milligan said in a statement Monday, “I am appreciative of the service Jim has given to the state of Arkansas from his time in the Governor’s Office, Department of Emergency Management and in my office.”

Singer, whom Milligan fired in April 2015, alleges in his suit that Harris defamed him by writing an interoffice email in which he speculated that Singer had mental problems and by taking steps to ensure that reporters saw the email. The suit also alleges that Milligan discriminated against Singer based on a perceived disability.

A new jury trial in the case is scheduled to begin Jan. 9 in U.S. District Court in Little Rock.

Harris’ retirement will be effective Jan. 13, according to Milligan spokesman Grant Wallace. Harris will use his accrued leave time until that date, Wallace said.

Harris’ annual salary is $105,050, according to the state’s transparency website.