diff --git a/pkg/obingslibrary/multimatch.go b/pkg/obingslibrary/multimatch.go
index cbd6ebf..b28befa 100644
--- a/pkg/obingslibrary/multimatch.go
+++ b/pkg/obingslibrary/multimatch.go
@@ -237,6 +237,14 @@ func (marker *Marker) beginFixedTagExtractor(
 		return ""
 	}
 
+	fe := begin - spacer
+	if fb > fe {
+		log.Panicf("On sequence: %s, begin %d is greater than end %d for a tag length of %d - begin:%d spacer:%d",
+			sequence.Id(),
+			fb, fe, taglength, begin, spacer,
+		)
+	}
+
 	return sequence.String()[fb:(begin - spacer)]
 }
 
diff --git a/pkg/obioptions/version.go b/pkg/obioptions/version.go
index 20de387..f2b2585 100644
--- a/pkg/obioptions/version.go
+++ b/pkg/obioptions/version.go
@@ -8,7 +8,7 @@ import (
 // corresponds to the last commit, and not the one when the file will be
 // commited
 
-var _Commit = "7b23985"
+var _Commit = "38dcd98"
 var _Version = "Release 4.4.0"
 
 // Version returns the version of the obitools package.