diff --git a/src/main/java/proteomics/Index/BuildIndex.java b/src/main/java/proteomics/Index/BuildIndex.java
index 4f517b9..3f0c3ae 100644
--- a/src/main/java/proteomics/Index/BuildIndex.java
+++ b/src/main/java/proteomics/Index/BuildIndex.java
@@ -84,7 +84,7 @@ public BuildIndex(Map<String, String> parameter_map) {
                 linker_mass = Float.valueOf(parameter_map.get("cl_mass")) - fix_mod_map.get('K');
             }
         } else if (linker_type == 2) {
-            linker_mass = Float.valueOf(parameter_map.get("cl_mass")) - fix_mod_map.get('C');
+            linker_mass = Float.valueOf(parameter_map.get("cl_mass"));
         } else {
             linker_mass = 0;
             logger.error("The cross-linker type cannot be recognized.");