DOUGLAS COUNTY, Colo. -- A Colorado State Patrol trooper was arrested Monday morning on suspicion of driving under the influence while in his patrol car.

Trooper David Dolan, 48, was arrested on the side of C-470 at the Platte River at 7:05 a.m.

The Douglas County Sheriff's Office received several calls from motorists reporting a marked CSP unit driving erratically on northbound Interstate 25 in the Castle Rock area, and then on C-470.

"I want to thank those people today that took the time and the initiative to make that difficult phone call to report a vehicle that was driving erratically down a road," said Col. James Wolfinbarger, Chief of the Colorado State Patrol. "I want to thank them. It helped keep a very bad situation from turning tragic."

Wolfinbarger called Monday the darkest day of his career.

"I'm devastated as a chief of an organization to stand here in front of you with images of seeing a member of our organization being escorted in handcuffs into a car," Wolfinbarger said.

The trooper was removed from his car and placed in handcuffs in the back of a Douglas County sheriff's unit.

"After contacting the driver, who was confirmed to be a Colorado state trooper in full uniform, he was taken into custody for investigation of driving under the influence of alcohol," said deputy Cocha Heyden, the public information officer for the Douglas County Sheriff's Office.

Heyden said Dolan was being booked on possible charges of driving under the influence and prohibited use of weapons. The weapons charge is a result of carrying a weapon while suspected of being under the influence.

Both the Douglas County Sheriff's Office and Colorado State Patrol are investigating.

“I am very concerned and disturbed regarding the events of this morning," said Wolfinbarger. "The Colorado State Patrol takes any violation of law and/or policy seriously and we will move quickly and thoroughly through this administrative investigation. While any violation of law is serious, this alleged act is very concerning given the nature of the mission of the Colorado State Patrol. We have a 75-year history of combating impaired and drunken driving and are deeply committed to eradicating this senseless crime on our roads."

Dolan will be placed on unpaid administrative leave pursuant to Colorado state personnel rules, Wolfinbarger said. He is a 21-year veteran of the patrol assigned to the selections unit for new recruits out of Colorado Springs.