diff --git a/src/data-structures/graph/Graph.js b/src/data-structures/graph/Graph.js
index e2ef20b7e0..8e603c389b 100644
--- a/src/data-structures/graph/Graph.js
+++ b/src/data-structures/graph/Graph.js
@@ -115,6 +115,9 @@ export default class Graph {
    */
   findEdge(startVertex, endVertex) {
     const vertex = this.getVertexByKey(startVertex.getKey());
+    if (!vertex) {
+      return null;
+    }
     return vertex.findEdge(endVertex);
   }
 
diff --git a/src/data-structures/graph/__test__/Graph.test.js b/src/data-structures/graph/__test__/Graph.test.js
index 1c6592ba55..be6e9d7fb2 100644
--- a/src/data-structures/graph/__test__/Graph.test.js
+++ b/src/data-structures/graph/__test__/Graph.test.js
@@ -87,9 +87,11 @@ describe('Graph', () => {
 
     const graphEdgeAB = graph.findEdge(vertexA, vertexB);
     const graphEdgeBA = graph.findEdge(vertexB, vertexA);
-    const graphEdgeAC = graph.findEdge(vertexB, vertexC);
+    const graphEdgeAC = graph.findEdge(vertexA, vertexC);
+    const graphEdgeCA = graph.findEdge(vertexC, vertexA);
 
     expect(graphEdgeAC).toBeNull();
+    expect(graphEdgeCA).toBeNull();
     expect(graphEdgeAB).toEqual(edgeAB);
     expect(graphEdgeBA).toEqual(edgeAB);
     expect(graphEdgeAB.weight).toBe(10);
@@ -108,9 +110,11 @@ describe('Graph', () => {
 
     const graphEdgeAB = graph.findEdge(vertexA, vertexB);
     const graphEdgeBA = graph.findEdge(vertexB, vertexA);
-    const graphEdgeAC = graph.findEdge(vertexB, vertexC);
+    const graphEdgeAC = graph.findEdge(vertexA, vertexC);
+    const graphEdgeCA = graph.findEdge(vertexC, vertexA);
 
     expect(graphEdgeAC).toBeNull();
+    expect(graphEdgeCA).toBeNull();
     expect(graphEdgeBA).toBeNull();
     expect(graphEdgeAB).toEqual(edgeAB);
     expect(graphEdgeAB.weight).toBe(10);