diff --git a/src/routes/tasks.js b/src/routes/tasks.js
index e0d28c067..32e6892e1 100644
--- a/src/routes/tasks.js
+++ b/src/routes/tasks.js
@@ -21,6 +21,7 @@ function stopTask(req, res, next) {
 
     tasks.stopTask(req.params.taskId, auditSource(req), function (error) {
         if (error && error.reason === TaskError.NOT_FOUND) return next(new HttpError(404, 'No such task'));
+        if (error && error.reason === TaskError.BAD_STATE) return next(new HttpError(409, error.message));
         if (error) return next(new HttpError(500, error));
 
         next(new HttpSuccess(204, {}));
diff --git a/src/tasks.js b/src/tasks.js
index ef35dd883..4a7cc77a1 100644
--- a/src/tasks.js
+++ b/src/tasks.js
@@ -103,7 +103,7 @@ function startTask(id, auditSource, callback) {
     assert.strictEqual(typeof auditSource, 'object');
     assert.strictEqual(typeof callback, 'function');
 
-    let taskInfo = TASKS[id];
+    const taskInfo = TASKS[id];
     if (!taskInfo) return callback(new TaskError(TaskError.NOT_FOUND, 'No such task'));
 
     let error = locker.lock(taskInfo.lock);
@@ -151,6 +151,9 @@ function stopTask(id, auditSource, callback) {
     assert.strictEqual(typeof auditSource, 'object');
     assert.strictEqual(typeof callback, 'function');
 
+    const taskInfo = TASKS[id];
+    if (!taskInfo) return callback(new TaskError(TaskError.NOT_FOUND, 'No such task'));
+
     if (!gTasks[id]) return callback(new TaskError(TaskError.BAD_STATE, 'task is not active'));
 
     debug(`stopTask: stopping task ${id}`);