diff --git a/Changes b/Changes
index f61104b..70a3538 100644
--- a/Changes
+++ b/Changes
@@ -3,6 +3,8 @@
         - indentation of </span> tags fixed
         - character entities used in DeReKo are automatically replaced by their corresponding characters
         - resources defined in Makefile
+        - fixed possible IO deadlock with KorAP tokenizer
+
 0.03 2021-01-12
         - Update KorAP-Tokenizer to released 2.0 version
         - Improve test suite for recent version
diff --git a/lib/KorAP/XML/TEI/Tokenizer/KorAP.pm b/lib/KorAP/XML/TEI/Tokenizer/KorAP.pm
index bbe38bd..d614dfe 100644
--- a/lib/KorAP/XML/TEI/Tokenizer/KorAP.pm
+++ b/lib/KorAP/XML/TEI/Tokenizer/KorAP.pm
@@ -31,7 +31,7 @@
       ($sentence_split? " --sentence-boundaries" : ""));
   $self->{sentence_split} = $sentence_split;
   $self->{name} = 'korap';
-  $self->{sep} = "\x{04}\n";
+  $self->{sep} = "\n\x{04}\n";
   return bless $self, $class;
 };
 
diff --git a/t/data/korap_tokenizer_challenge.xml b/t/data/korap_tokenizer_challenge.xml
new file mode 100644
index 0000000..a37c3dc
--- /dev/null
+++ b/t/data/korap_tokenizer_challenge.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE idsCorpus>
+<idsCorpus version="1.0" TEIform="teiCorpus.2">
+  <idsDoc id="A00" type="text" version="1.0" TEIform="TEI.2">
+    <idsText id="WDD19.H0039.87242" n="de.Diskussion:Hilfswerk_der_Evangelischen_Kirchen_der_Schweiz" version="1">
+      <idsHeader type="text" pattern="text" version="1.0">
+        <fileDesc>
+          <titleStmt>
+            <textSigle>WDD19/H0039.87242</textSigle>
+          </titleStmt>
+        </fileDesc>
+      </idsHeader>
+      <text>
+        <body>
+          <div>
+            <p>?____</p>
+          </div>
+        </body>
+      </text>
+    </idsText>
+  </idsDoc>
+</idsCorpus>
diff --git a/t/script.t b/t/script.t
index fbe28bf..773bb60 100644
--- a/t/script.t
+++ b/t/script.t
@@ -175,6 +175,26 @@
     ->element_count_is('spanList span', 227);
 };
 
+subtest 'Check KorAP tokenizer for infinite loop bug' => sub {
+
+  my $file = catfile($f, 'data', 'korap_tokenizer_challenge.xml');
+
+  eval {
+    require KorAP::XML::TEI::Tokenizer::KorAP;
+    1;
+  } or do {
+    plan skip_all => "KorAP::XML::TEI::Tokenizer::KorAP cannot be used";
+  };
+
+  test_tei2korapxml(
+    file => $file,
+    param => "-tk -s",
+    tmp => 'script_bug_check'
+  )
+    ->stderr_like(qr!tei2korapxml: .*? text_id=WDD19_H0039\.87242!)
+    ->file_readable('WDD19/H0039/87242/struct/structure.xml');
+};
+
 subtest 'Sentence split with KorAP tokenizer' => sub {
 
   eval {