A Lusk man appeared in Natrona County District Court on Thursday and entered not guilty pleas to three felony charges stemming from a crash on Highway 220 last year that killed a woman and her infant son.

Alexander Sebastian Richardson, 33, is charged with two counts of aggravated homicide by vehicle and one count of aggravated assault. He could face up to 50 years in prison if convicted on all charges.

On the afternoon of August 23, 2017, Richardson was driving from his work site in Utah back to his home in Lusk.

At roughly 1:20 p.m., Richardson's Ford F-250 drifted across the centerline into the westbound lane, where it collided head-on with a Ford Explorer carrying 46-year-old Soon Young Lee, Bong Jun Seo and 3-year-old Jaehyeok Seo. That's according to a crash report from the Wyoming Highway Patrol.

According to an affidavit filed in the case, witnesses said that Lee evidently died immediately. The infant had a pulse when a Carbon County nurse stopped at the scene and rendered aid, but the child's pulse was lost within a few minutes and the nurse began to perform CPR.

The nurse told investigators that the baby had a head wound and possible broken neck. She continued CPR until Life Flight arrived, but the child did not survive.

Seo was injured, but survived.

At the time of Thursday's arraignment before District Judge Thomas Sullins, Richardson was free on $7,500 cash bond. He is allowed to travel within Wyoming, Colorado and Utah for work.

His attorney, Don Fuller, told Sullins that a scheduling conference would likely be necessary to address administrative issues ahead of trial. Fuller and Assistant District Attorney Michael Schafer each told Sullins that any trial would last at least five days.

Fuller attributed the reason for such a long trial to what he called the likelihood of "dueling experts."

Following Thursday's arraignment hearing, Fuller told K2 Radio News that he has hired Littleton, Colorado-based OEC Forensics to perform an independent reconstruction of the crash.