HOULTON, Maine — A 24-year veteran of the Maine State Police was on administrative leave Monday after she was cited for operating her state police cruiser while under the influence of alcohol last week, state police said.

Sgt. Julie Bergan, 54, was issued a summons Thursday for OUI after she failed field sobriety and blood-alcohol content tests at the Houlton barracks, state police Lt. Col. Raymond Bessette said Monday.

Bessette called the incident “a tragic chain of events.”

“We hold ourselves to the highest standards, and as difficult as this situation is we need to ensure that we hold true to the core values of Maine State Police,” he added.

Attempts to reach Bergan for comment were not successful on Monday.

Under Maine law, people may be issued an OUI summons when they are found driving a motor vehicle with a blood alcohol content of 0.08 percent or more.

Bessette referred comment on Bergan’s blood alcohol test results to Todd Collins, district attorney for Aroostook County. Collins did not return a telephone message seeking comment.

The incident began sometime Thursday morning, Bessette said. Bergan reported for work in her state police-issued cruiser and her supervisor, Lt. Mark Brooks, and several co-workers saw her behaving in what they believed to be an erratic manner.

State police administrators then ordered her field-tested and the summons was issued, Bessette said.

Bergan is on administrative leave pending the outcome of an internal investigation conducted by Lt. Erik Baker, who heads the Internal Affairs Division at state police headquarters in Augusta, Bessette said.

Bergan joined state police in 1988 and was promoted to sergeant in 1997, Bessette said.

State police typically are eligible for retirement after serving 25 years, Bessette said.

Bergan is due in Houlton District Court on Aug. 7.

Another Maine state trooper pleaded guilty to a drunken driving charge on Jan. 24.

A judge fined Robin Parker $500 and suspended his driver’s license for 90 days. The Department of Public Safety also suspended him for two months without pay and demoted him from sergeant to trooper.

Parker was issued a summons for drunken driving after he was stopped on Dec. 18 on the Maine Turnpike in Gray after a motorist called to report that his vehicle was being driven erratically.

The Associated Press contributed to this report.