In the time since the crash happened, more than a month ago, police -- and we here at News 13 -- have gotten a lot of calls from people wondering why it took so long to take action.
Actually, they were expecting him to turn himself in. Officials say they never lost touch with Arthur throughout the entire investigation process.
There are still a lot of people wondering why it took so long for this day to come.
District Attorney Michael Blonigen says, "he contacted us yesterday through an attorney and we arranged for him to surrender himself this morning without any difficulty."
Lamont Arthur Junior wasn't placed in custody after failing a field sobriety test, but officials say they wanted to avoid a double jeopardy situation.
Sgt. Rich Brown says, "it was a complex investigation with a lot of moving parts. A lot of people wanted him arrested initially on scene for a DUI which would be a misdemeanor, but that also gives the person an opportunity to bond out and creates a double jeopardy situation when we come with more serious charges down the road."
Basically, had Arthur Junior been placed into custody that night for a DUI, he could have paid a $750 bond and walked free without being tried for aggravated vehicular homicide at all.
Officials say they wanted all their ducks in a row.
Blonigen says, "we can't just hold him because he's a suspect. We have to charge somebody with a crime to hold them. But we want to make sure that's the right charge, otherwise we can cross both legal and evidentiary problems with our case."
And Casper officials say they kept tabs on Arthur Junior from day one.
Brown says, "we were in contact with Lamont Arthur Junior during the whole investigation. We knew where he was at. He agreed to turn himself in, and he did turn himself in this morning."
Officer Joe Nickerson says, "cases like this can be very frustrating though because it's hard for the public to understand the procedure that we use. And it's been explained the double jeopardy issue, the reason why we did not charge him with a DUI initially while we had to wait until we had our entire case built."
Sergeant Brown says people may have been frustrated... But they feel they did what they had to.
"We're looking for justice for the family, you know. I could do something like that, but that would jeopardize justice for both parties. We're a neutral party and I understand that somebody was killed and we understand that and we want to put together a strong case ."
Arthur Junior could spend up to 20 years in prison if convicted of the vehicular homicide charge and a maximum of 10 years if found guilty of the aggravated assault charge... Those terms could run concurrently.
Blonigen says the deceased Harker's wife, Stacy, is being kept up-to-date on the situation. She was in the courtroom this afternoon and told News 13 it was a huge relief to see him arrested.