A Layton teenager was ordered to undergo a 90-day evaluation at the Utah State Prison for his part in the August shotgun assault on a Utah Highway Patrol trooper.

Jared L. Valentine, 18, 631 E. 20th North, pleaded guilty to two third-degree felonies in a plea negotiation with the Davis County attorney's office and was sentenced Friday in 2nd District Court. Judge Rodney S. Page set a new sentencing date of March 7, 1989.Valentine and Michael K. Polete, 18, 610 E. 20th North, Layton, were originally charged with attempted criminal homicide in the Aug. 8 assault on UHP trooper John T. Mitchell in Layton.

Mitchell pursued a car that ran a stop sign about 3 a.m. After a high-speed pursuit that wound through Layton's rural area, several shotgun blasts from the driver's side of the car struck Mitchell's patrol car, disabling it.

Valentine admitted to being a passenger in the car and Polete has admitted driving it and firing the shots at Mitchell, who suffered minor injuries from flying glass and debris.

Polete pleaded guilty to a reduced charge of failure to stop at the command of a police officer and burglary in the July 22 burglary of a Layton convenience store in which a safe containing more than $3,000 in cash and checks was taken.

At Friday's sentencing, defense attorney Robert Echard said although Valentine has a juvenile record that includes several burglaries, his refusal to fire at the trooper shows a strength of character.

Polete is scheduled for sentencing Dec. 20. In a separate plea bargain, Polete pleaded guilty to attempted second-degree homicide and theft, both second-degree felonies.