State v. Louser, 890 N.W.2d 1

Defendant Alexander Justin Pittenger was charged with corruption/solicitation of a minor and gross sexual imposition; gross sexual imposition was later dismissed and retrial on the solicitation charge began January 9, 2017.
At a prior July 2016 trial Special Agent Dale Maixner (Ret.) testified; that trial ended in mistrial.
On the first day of the January 2017 retrial the State sought to call Special Agent Pat Helfrich; Pittenger objected because Helfrich was never disclosed as an expert witness.
The district court ruled Helfrich was an expert and excluded his testimony as undisclosed expert evidence, expressing concern the State was "playing switcharoo" by tailoring testimony.
The State obtained a stay with the jury impaneled and petitioned the North Dakota Supreme Court for a supervisory writ to allow Helfrich to testify as a lay witness.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the district court properly excluded Helfrich as an undisclosed expert	State: Helfrich may testify as a lay witness or limited witness; exclusion was premature	Pittenger: Helfrich is effectively an expert and was not disclosed as required under discovery rules	Court: District court's exclusion was premature; vacate order and allow testimony, ruling to be made as testimony is offered whether it is fact (401), lay opinion (701), or expert opinion (702)
Whether supervisory relief is appropriate	State: No adequate remedy by appeal given impaneled jury and double jeopardy/appeal limits	Pittenger: Implicitly opposed; district court's protection of defense from surprise	Court: Supervisory jurisdiction warranted because jury impaneled and State lacks adequate alternative remedy

State, ex rel. Madden v. Rustad, 823 N.W.2d 767 (2012) (describing narrow, discretionary use of supervisory writs)
State v. Bernsdorf, 784 N.W.2d 126 (2010) (limitations on State's right to appeal after acquittal)
State v. Deutscher, 766 N.W.2d 442 (2009) (appealability constraints and supervisory relief context)
State v. Holte, 631 N.W.2d 595 (2001) (noting practical limits on when the State can raise issues on appeal)
State v. Sabinash, 574 N.W.2d 827 (1998) (same)
State v. Saulter, 764 N.W.2d 430 (2009) (distinguishing specialized knowledge used for expert testimony from testimony that is product of investigation)