Colorado state Trooper Jaimie Jursevics stood along Interstate 25 late Sunday, waving a flashlight to summon a suspected drunk driver to the shoulder.

While a witness watched and listened from a car behind, Jursevics screamed as she was hit by the pickup truck, according to an arrest affidavit. Her flashlight tumbled through the air as she was thrown onto the roadway in Castle Rock where she lay without a pulse.

Several miles away, the driver of the pickup, retired Army Col. Eric Peter Henderson, was arrested after investigators say he answered an officer’s questions through glassy eyes, slurred speech and the smell of alcohol.

“I killed a cop,” Henderson later told detectives through tears, according to the affidavit released Monday.

Henderson, of Peyton, is being held at the Douglas County jail in lieu of a $1 million bond. The highly decorated 52-year-old’s booking mugshot showed him frowning and clad in a Peyton Manning jersey he was wearing home from watching the Broncos game earlier in the day.

A friend told investigators Henderson had at least six beers while in Denver for the team’s matchup with the Chiefs, according to the affidavit.

Jursevics, who joined the Colorado State Patrol in January 2011 and began working at the agency’s Castle Rock office in 2014, is survived by her husband and 8-month-old daughter, according to a GoFundMe site.

“Our family has been hurt today,” Chief Scott Hernandez said in a statement. “A senseless act has taken the life of someone who swore to protect Colorado.”

Jursevics was struck about 9 p.m. as she was investigating a crash on the interstate just north of Tomah Road. Authorities say she tried to stop Henderson’s truck after another motorist called in to report him as possibly driving under the influence.

Henderson’s passenger, Craig Whitehill, told investigators the two were together at the Broncos’ game but that nothing about Henderson’s driving concerned him.

Whitehill said he fell asleep during the trip south and was awakened by a “big thump,” the affidavit says.

Henderson was arrested on suspicion of several charges, including vehicular homicide, driving under the influence and careless driving resulting in death, records show.

Henderson, when asked about front-end damage to his truck, initially told an officer “nothing” had happened, according to the affidavit. Investigators say Henderson “looked very shocked” as he was told of the charges he was facing, repeatedly asking deputies to repeat the allegations.

Efforts to reach Henderson’s family on Monday were unsuccessful.

DOCUMENT: Eric Henderson arrest affidavit

The Army said Henderson retired in 2013 out of Fort Carson. He worked in the Space and Missile Defense Command/Army Forces Strategic Command at Peterson Air Force Base in Colorado Springs, according to a news release.

The Mountain Post’s release said he was in the military for 27 years where he last acted as a commander. Henderson was deployed six times, including surrounding both Iraq wars and on several occasions to Kuwait, Army records show.

Henderson is listed as a program manager at Colorado Professional Resources LLC’s website, and a receptionist confirmed his employment there on Monday morning.

The Colorado Springs-based group’s site says the company offers support for satellite and missile defense systems, including on some of the “most critical national security programs.”

Henderson is also listed as the president of Mountain and Plains Appaloosa Horse Club.

“He’s a family man,” said Nancy Nemmers, who serves as vice president of the club. “He has horses. It’s kind of heartbreaking to think this has happened. It’s hard for me to believe it did happen.”

“I’m a little bit in shock, for both families,” she added. “It’s a horrible tragedy.”

Colorado Bureau of Investigation records show no previous arrests for Henderson in Colorado. Henderson is due in court Tuesday for a first appearance in the case.

Law enforcement and emergency service agencies from throughout the state offered their sympathies to the State Patrol.

“Our sincere condolences to the family and friends of the trooper killed this morning on I-25, just doing her job!” the Glendale Police Department said in a Facebook post.

The sheriff’s office said an investigation into the collision remains open and asked anyone with information on the case to call 303-660-7579.

Jesse Paul: 303-954-1733, jpaul@denverpost.com or @JesseAPaul