diff --git a/src/tcp_rules.c b/src/tcp_rules.c
index d81ffe3..7fbc389 100644
--- a/src/tcp_rules.c
+++ b/src/tcp_rules.c
@@ -699,7 +699,7 @@
 			memprintf(err,
 			          "'%s %s %s' : fetch method '%s' extracts information from '%s', none of which is available here",
 			          args[0], args[1], args[kw], args[arg-1], sample_src_names(expr->fetch->use));
-			free(expr);
+			release_sample_expr(expr);
 			return -1;
 		}
 
@@ -709,7 +709,7 @@
 				memprintf(err,
 					  "'%s %s %s' : missing length value",
 					  args[0], args[1], args[kw]);
-				free(expr);
+				release_sample_expr(expr);
 				return -1;
 			}
 			/* we copy the table name for now, it will be resolved later */
@@ -718,7 +718,7 @@
 				memprintf(err,
 					  "'%s %s %s' : length must be > 0",
 					  args[0], args[1], args[kw]);
-				free(expr);
+				release_sample_expr(expr);
 				return -1;
 			}
 			arg++;
@@ -777,7 +777,7 @@
 			memprintf(err,
 			          "'%s %s %s' : fetch method '%s' extracts information from '%s', none of which is available here",
 			          args[0], args[1], args[kw], args[arg-1], sample_src_names(expr->fetch->use));
-			free(expr);
+			release_sample_expr(expr);
 			return -1;
 		}
 
@@ -790,7 +790,7 @@
 				memprintf(err,
 					  "'%s %s %s' : missing table name",
 					  args[0], args[1], args[kw]);
-				free(expr);
+				release_sample_expr(expr);
 				return -1;
 			}
 			/* we copy the table name for now, it will be resolved later */