diff --git a/index.go b/index.go
index 58543f2..cf7dc32 100644
--- a/index.go
+++ b/index.go
@@ -331,6 +331,15 @@ func (idx *faissIndex) Reconstruct(key int64) (recons []float32, err error) {
 func (idx *faissIndex) ReconstructBatch(keys []int64, recons []float32) ([]float32, error) {
 	var err error
 	n := int64(len(keys))
+	if recons == nil {
+		recons = make([]float32, n*int64(idx.D()))
+	}
+
+	// exit in case of invalid input
+	if n == 0 || len(recons) != int(n)*idx.D() {
+		return nil, fmt.Errorf("invalid input")
+	}
+
 	if c := C.faiss_Index_reconstruct_batch(
 		idx.idx,
 		C.idx_t(n),