The Basic Law Enforcement Academy is investigating how the material was circulated, The Seattle Times reported Monday.
Director Sue Rahr, the former King County sheriff, said she was "deeply disappointed" in recruits who used or had knowledge of the material.
"It tarnishes the integrity of our profession and damages public trust," Rahr said Sunday in a statement.
The materials were likely used by recruits to memorize items they knew would be on the test.
The materials date back several years, but it's unknown how long they have been circulating, Rahr said. They were on a computer thumb drive shared by recruits in two of three classes currently training at the academy in Burien.
The use of unauthorized study materials was reported Thursday by one recruit.
The academy is operating as if all tests have been compromised. Recruits will have to pass new tests to graduate.
The written test is just one step in becoming a police officer. It's unlikely the compromised test materials would allow an unqualified candidate to pass, the academy said. Recruits also must demonstrate their knowledge in field tests. And they undergo additional training with police agencies.
The academy trains officers for police departments statewide, except for the Washington State Patrol which conducts its own training for troopers.
The academy offers a 720-hours basic curriculum. It includes criminal law procedures, traffic enforcement, cultural awareness, firearms training, and defensive tactics.
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