Authorities are hoping that photos of the knife set may jog the memory of someone who may have found a knife of this type or who knows someone with this type of knife.
Cowell died in February after she was hit on the head, strangled and stabbed in the neck. Her body was dumped along the Columbia River.
Officials said the murder knife was only sold as part of a Maxam sportsman's cutlery set. Within the Wenatchee area, the set was only sold at Stans Merry Mart on South Wenatchee Avenue within the past two years.
Photo shows the boxed set of knives used in the killing of 17-year-old Mackenzie Cowell of Wenatchee.
Two sets were also given away at 5-T’s Restaurant and Lounge in East Wenatchee as a pull tab prize.
The set is manufactured by Maxam and has a unique black-and-gray handle.
Wenatchee police spokesman Capt. Doug Jones said a knife from this type of set was found near Mackenzie's body, and was used to kill her.
He said information about the knife was not immediately released because it would only have been known by the killer and investigators, and could have been an important clue in questioning suspects.
But task force members now believe it may be more helpful to release the information in hopes it may jog the memory of someone who has seen a knife like it.
Anyone who may have found a knife from this set or who knows someone who had possession of a knife or knives from this set is asked to contact the Cowell Homicide Task force at (509) 663-9911.
A $54,000 reward has been offered for information leading to the arrest and prosecution of Mackenzie's killer.
Cowell was last seen Feb. 9 in Wenatchee leaving a beauty school class at the Academy of Hair Design.
Detectives have determined that she was likely at the Wenatchee Riverfront Park boat ramp area a little later that same day.
It is not known why she was at the park, or whether she met anyone there.
Her body was found four days later about 30 miles from Wenatchee along the Columbia River at Crescent Bar.
Jones said authorities are also continuing to follow up on other leads as they try to identify Mackenzie's killer, but no suspects or persons of interest have yet been identified.