CONCORD, N.H. — A veteran New Hampshire county attorney and his deputy have been ordered off the job amid an investigation, the state attorney general and federal prosecutors said Thursday.

Rockingham County Attorney Jim Reams was stripped of his prosecutorial authority Wednesday and told not to return to his office. Deputy Tom Reid was put on paid administrative leave. Reams and Reid prosecuted major crimes and high-profile cases.

State and federal officials would not say why they’re investigating Reams, except to say they’ve received complaints about the office.

“When we have additional information we will announce it,” said Senior Assistant Attorney General Jane Young, who heads the criminal bureau.

Senior Assistant Attorney General James Boffetti will serve as interim county attorney while the investigation is underway.

Reams, who has been county attorney since 1998, did not immediately return a call seeking comment. A message seeking comment was also left with Reid.

Boffetti said he learned of his interim role Wednesday night and was at the county attorney’s office Thursday to brief staff before the official announcement of the investigation. He said the office is functioning as it should, even while staff members are being questioned by investigators.

U.S. Attorney John Kacavas said investigators are “at the beginning stages” of the probe.

“It’s important to do this as expeditiously as possible,” Kacavas said. “It may take a few days or it might take a few weeks.” He would not indicate whether the FBI or other agencies have obtained or used search warrants.

Boffetti said his appointment as interim attorney had nothing to do with his role as head of unit that investigates financial fraud and consumer protection complaints at the attorney general’s office. Before joining the attorney general’s office six years ago, Boffetti was a public defender in Rockingham County for 14 years, including more than a decade heading the office.

“This is a very difficult, stressful time for people who work here,” Boffetti said. “They wanted someone who knows them and knows what they do.”

Among the cases Reams prosecuted was a child abuse probe against a mother and her boyfriend charged with burning and beating the woman’s 3-year-old. They were arrested at a theme park in Florida. The mother has pleaded guilty and been sentenced to 21/2 years in prison; charges are still pending against the boyfriend.