Written by Brian Maass

GOLDEN, Colo. (CBS4) – CBS4 has learned the Jefferson County Sheriff’s Department has identified a suspect in a police impersonation case from last month and a sheriff’s deputy is also under investigation for allegedly being involved in the case.

“We’re pretty disappointed,” said Jefferson County Sheriff Ted Mink.

The incident took place at about 6 p.m. on July 31 near the intersection of Bowles and Wadsworth. A civilian reported that an unmarked white Crown Victoria activated emergency lights and attempted to pull over a single female driver.

The woman did not pull over and no actual contact was made between the driver of the Crown Vic and the female driver.

Authorities tracked the suspect vehicle’s license plate to a home in Centennial. They have questioned the Centennial man who was believed to be driving the car.

“He is going to be charged with something,” said Jacki Kelley, a spokeswoman for the Jefferson County Sheriff’s Department.

Kelley declined to identify the driver, who is not in law enforcement, until an actual criminal case has been filed.

During the course of the investigation Kelley said investigators learned a Jefferson County Sheriff’s department deputy, who works in the jail, was in the suspect’s car when the attempted stop took place.

She said an active internal affairs investigation is under way into the deputy’s conduct, although she said he is not suspected of criminal activity.

Jefferson County Sheriff Detention Services Division (credit: CBS)

Kelley declined to identify the deputy until the investigation is complete.

“We are going to look at his conduct and his actions that he took to figure out what he did do, or should have done that he didn’t do and follow the right recourse,” said Kelley.

The deputy has not been placed on any kind of administrative leave. The department says the allegations are embarrassing.

“The sheriff is extremely disappointed that one of his deputies may have had some involvement, any involvement whatsoever in something like this,” said Kelley.

Kelley emphasized the deputy was only thought to be connected to this one case, not to several other police impersonation cases that have taken place around the metro area over the last several months.