diff --git a/protected/java/src/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixSplitter.java b/protected/java/src/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixSplitter.java
index f3a41ee8b..dabfbb322 100644
--- a/protected/java/src/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixSplitter.java
+++ b/protected/java/src/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixSplitter.java
@@ -48,6 +48,7 @@ package org.broadinstitute.sting.gatk.walkers.haplotypecaller.graphs;
 
 import com.google.java.contract.Requires;
 
+import java.io.File;
 import java.util.*;
 
 /**
@@ -150,10 +151,14 @@ public class CommonSuffixSplitter {
      * @return true if we can safely split up toMerge
      */
     private boolean safeToSplit(final SeqGraph graph, final SeqVertex bot, final Collection<SeqVertex> toMerge) {
+        final Set<SeqVertex> outgoingOfBot = new HashSet<SeqVertex>(graph.outgoingVerticesOf(bot));
         for ( final SeqVertex m : toMerge ) {
             final Set<BaseEdge> outs = graph.outgoingEdgesOf(m);
             if ( m == bot || outs.size() != 1 || ! graph.outgoingVerticesOf(m).contains(bot) )
-                // m == bot => don't allow cycles in the graph
+                // m == bot => don't allow self cycles in the graph
+                return false;
+            if ( outgoingOfBot.contains(m) )
+                // forbid cycles from bottom -> mid
                 return false;
         }
 
diff --git a/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixMergerUnitTest.java b/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixMergerUnitTest.java
index 012add769..8682ae5e4 100644
--- a/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixMergerUnitTest.java
+++ b/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixMergerUnitTest.java
@@ -72,6 +72,15 @@ public class CommonSuffixMergerUnitTest extends BaseTest {
             this.v = v;
             this.commonSuffix = commonSuffix;
         }
+
+        @Override
+        public String toString() {
+            return "SplitMergeData{" +
+                    "graph=" + graph +
+                    ", v=" + v +
+                    ", commonSuffix='" + commonSuffix + '\'' +
+                    '}';
+        }
     }
 
     public static Object[][] makeSplitMergeData(final int maxTests) {
diff --git a/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixSplitterUnitTest.java b/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixSplitterUnitTest.java
index f03dc8762..8006cb18d 100644
--- a/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixSplitterUnitTest.java
+++ b/protected/java/test/org/broadinstitute/sting/gatk/walkers/haplotypecaller/graphs/CommonSuffixSplitterUnitTest.java
@@ -51,13 +51,18 @@ import org.testng.Assert;
 import org.testng.annotations.DataProvider;
 import org.testng.annotations.Test;
 
+import java.io.File;
+import java.util.Arrays;
+
 public class CommonSuffixSplitterUnitTest extends BaseTest {
+    private final static boolean DEBUG = false;
+
     @DataProvider(name = "SplitData")
     public Object[][] makeSplitData() {
         return CommonSuffixMergerUnitTest.makeSplitMergeData(-1);
     }
 
-    @Test(dataProvider = "SplitData")
+    @Test(dataProvider = "SplitData", enabled = !DEBUG)
     public void testSplit(final CommonSuffixMergerUnitTest.SplitMergeData data) {
         final boolean expectedMerge = ! data.commonSuffix.isEmpty() && data.graph.inDegreeOf(data.v) > 1;
 
@@ -74,7 +79,7 @@ public class CommonSuffixSplitterUnitTest extends BaseTest {
         CommonSuffixMergerUnitTest.assertSameHaplotypes(String.format("suffixSplit.%s.%d", data.commonSuffix, data.graph.vertexSet().size()), data.graph, original);
     }
 
-    @Test
+    @Test(enabled = !DEBUG)
     public void testSplitPrevHaveMultipleEdges() {
         final SeqGraph original = new SeqGraph();
         final SeqVertex v1 = new SeqVertex("A");
@@ -93,7 +98,7 @@ public class CommonSuffixSplitterUnitTest extends BaseTest {
         Assert.assertFalse(new CommonSuffixSplitter().split(original, v3), "Cannot split graph with multiple outgoing edges from middle nodes");
     }
 
-    @Test
+    @Test(enabled = !DEBUG)
     public void testSplitNoCycles() {
         final SeqGraph original = new SeqGraph();
         final SeqVertex v1 = new SeqVertex("A");
@@ -110,4 +115,28 @@ public class CommonSuffixSplitterUnitTest extends BaseTest {
         original.addEdges(v4, v4);
         Assert.assertFalse(new CommonSuffixSplitter().split(original, v4), "Cannot split graph with a cycle of the bottom list");
     }
+
+    @Test(timeOut = 10000)
+    public void testSplitComplexCycle() {
+        final SeqGraph original = new SeqGraph();
+        final SeqVertex r1 = new SeqVertex("ACTG");
+        final SeqVertex r2 = new SeqVertex("ATGC");
+        final SeqVertex cat1 = new SeqVertex("CAT");
+        final SeqVertex cat2 = new SeqVertex("CAT");
+        final SeqVertex c1 = new SeqVertex("C");
+        final SeqVertex c2 = new SeqVertex("C");
+
+        original.addVertices(r1, r2, cat1, cat2, c1, c2);
+        original.addEdges(r1, cat1, c1, cat2, c1);
+        original.addEdges(r2, c2, cat2);
+
+        original.printGraph(new File("testSplitComplexCycle.dot"), 0);
+
+        for ( final SeqVertex v : Arrays.asList(cat2) ) { // original.vertexSet() ) {
+            final SeqGraph graph = (SeqGraph)original.clone();
+            final boolean success = new CommonSuffixSplitter().split(graph, v);
+            if ( success ) graph.printGraph(new File("testSplitComplexCycle.fail.dot"), 0);
+            Assert.assertFalse(success, "Shouldn't be able to split any vertices but CommonSuffixSplitter says it could for " + v);
+        }
+    }
 }