diff --git a/app/controllers/admin/police_districts_controller.rb b/app/controllers/admin/police_districts_controller.rb
index 0088700..ecff7be 100644
--- a/app/controllers/admin/police_districts_controller.rb
+++ b/app/controllers/admin/police_districts_controller.rb
@@ -1,6 +1,8 @@
 class Admin::PoliceDistrictsController < Admin::ApplicationController
   include GoogleCalendarable
 
+  before_action :set_district, except: [:new, :create, :index]
+
   def new
     @district = PoliceDistrict.new
 
@@ -19,17 +21,14 @@ def create
   end
 
   def show
-    @district = PoliceDistrict.find_by_slug(params[:id])
+    render :show
   end
 
   def edit
-    @district = PoliceDistrict.find_by_slug(params[:id])
-
     render :edit
   end
 
   def update
-    @district = PoliceDistrict.find_by_slug(params[:id])
     if @district.update(district_params)
       redirect_to admin_police_districts_path
     else
@@ -43,6 +42,10 @@ def index
 
   private
 
+  def set_district
+    @district = PoliceDistrict.find_by_slug!(params[:id])
+  end
+
   def district_params
     params.require(:police_district).permit(
       :name,
diff --git a/spec/controllers/admin/police_districts_controller_spec.rb b/spec/controllers/admin/police_districts_controller_spec.rb
new file mode 100644
index 0000000..73f1b08
--- /dev/null
+++ b/spec/controllers/admin/police_districts_controller_spec.rb
@@ -0,0 +1,46 @@
+require 'rails_helper'
+
+RSpec.describe Admin::PoliceDistrictsController, type: :controller do
+  let(:user) { FactoryBot.create(:user) }
+  let!(:district) { FactoryBot.create(:police_district, slug: 'oakland', timezone: 'Pacific Time (US & Canada)') }
+
+  context 'when user is signed in' do
+    before do
+      sign_in user
+    end
+
+    describe '#update' do
+      it 'returns 404 if district not present' do
+        expect do
+          post :update, params: { id: 'asldkfjaslkfdj' }
+        end.to raise_exception(ActiveRecord::RecordNotFound)
+      end
+    end
+
+    describe '#edit' do
+      render_views
+
+      it 'returns 404 if district not present' do
+        expect do
+          post :edit, params: { id: 'asldkfjaslkfdj' }
+        end.to raise_exception(ActiveRecord::RecordNotFound)
+      end
+    end
+
+    describe '#destroy' do
+      it 'returns 404 if district not present' do
+        expect do
+          post :update, params: { id: 'asldkfjaslkfdj' }
+        end.to raise_exception(ActiveRecord::RecordNotFound)
+      end
+    end
+
+    describe '#show' do
+      it 'returns 404 if district not present' do
+        expect do
+          get :show, params: { id: 'asldkfjaslkfdj' }
+        end.to raise_exception(ActiveRecord::RecordNotFound)
+      end
+    end
+  end
+end