Owen M. Van Duyn—Perjurer or Public servant doing his legal duty?

You have seen similar 'postale' cards on this blog as the one below showing the Caldwell Banking & Trust Co. in Caldwell, Idaho. I have various images of the bank, including several of this same view, so I am usually not looking for any more. However, this one is a bit unique in that it was sent, written on, and signed by a significant player in the investigation of Frank Steunenberg's murder, the subsequent arrest in Colorado of Haywood, Pettibone and Moyer, and the trial of Big Bill Haywood. No, not Darrow, Borah or Hawley, but a major force in Idaho legal circles nonetheless— Owen M. Van Duyn.
Click on the image to enlarge for viewing.

We can see that Van Duyn wasted little time in taking over the upstairs of the bank, including Frank's corner office. Written on the front: "Caldwell, Idaho, December 22, 1906. The offices marked with a X are my law offices. Owen W. VanDuyn."

Van Duyn was elected Attorney for Canyon County in 1905, served three terms/six years, and was holding that office when Frank Steunenberg was assassinated on December 30, 1905. This post card was mailed/dated by Van Duyn almost exactly one year later—December 22, 1906.

The core of the prosecution team was, L to R: William Borah; Owen M. Van Duyn, county attorney of Canyon County (standing); William A. Stone representing the Steunenberg Family & other Caldwell interests; and James Hawley.—From Big Trouble.

It was as Attorney for Canyon County, and working in concert with Pinkerton Detective James McParland and Governor Frank Gooding, that Van Duyn swore out a complaint (sometimes referred to as the perjured affidavit), against Haywood, Moyer and Pettibone.

So was it perjury or was Van Duyn acting legally within the sworn duty of his office?  And what about the subsequent apprehension of Haywood, Pettibone and Moyer in  Colorado by Idaho authorities and transport by train back to Boise to stand trial? Kidnapping or a legal arrest?  What is your opinion?  More to come.

I have not researched to any degree, but I am guessing the card is addressed to Owen's sister in Oregon where many of the Van Duyn's resided and had attended school.