diff --git a/cpp/include/raft/spatial/knn/knn.hpp b/cpp/include/raft/spatial/knn/knn.hpp
index ccee635701..cb7d596366 100644
--- a/cpp/include/raft/spatial/knn/knn.hpp
+++ b/cpp/include/raft/spatial/knn/knn.hpp
@@ -51,7 +51,7 @@ using deviceAllocator = raft::mr::device::allocator;
  * 					 form (e.g., without raising to the 1/p power).
  */
 void brute_force_knn(
-  raft::handle_t &handle, std::vector<float *> &input, std::vector<int> &sizes,
+  raft::handle_t const &handle, std::vector<float *> &input, std::vector<int> &sizes,
   int D, float *search_items, int n, int64_t *res_I, float *res_D, int k,
   bool rowMajorIndex = false, bool rowMajorQuery = false,
   distance::DistanceType metric = distance::DistanceType::L2Unexpanded,