diff --git a/src/com/SZZ/jiraAnalyser/git/Git.java b/src/com/SZZ/jiraAnalyser/git/Git.java
index 4e2f69c..3f797ec 100644
--- a/src/com/SZZ/jiraAnalyser/git/Git.java
+++ b/src/com/SZZ/jiraAnalyser/git/Git.java
@@ -296,7 +296,7 @@ public  String getBlameAt(String commitSha, String file, int lineNumber) {
 		      blamer.setStartCommit(commitID);
 		      blamer.setFilePath(file);
 		      blame = blamer.call();}
-		      RevCommit commit = blame.getSourceCommit(lineNumber);
+		      RevCommit commit = blame.getSourceCommit(lineNumber - 1);
 		      return commit.getName();
 		} catch (Exception e) {
 			return null;