diff --git a/src/scalib_ext/scalib-py/src/factor_graph.rs b/src/scalib_ext/scalib-py/src/factor_graph.rs
index ee8cf907..b467b390 100644
--- a/src/scalib_ext/scalib-py/src/factor_graph.rs
+++ b/src/scalib_ext/scalib-py/src/factor_graph.rs
@@ -58,13 +58,15 @@ impl FactorGraph {
     }
 
     pub fn __getstate__(&self, py: Python) -> PyResult<PyObject> {
-        Ok(PyBytes::new(py, &serialize(&self.inner.as_deref()).unwrap()).to_object(py))
+        let to_ser: Option<&sasca::FactorGraph> = self.inner.as_deref();
+        Ok(PyBytes::new(py, &serialize(&to_ser).unwrap()).to_object(py))
     }
 
     pub fn __setstate__(&mut self, py: Python, state: PyObject) -> PyResult<()> {
         match state.extract::<&PyBytes>(py) {
             Ok(s) => {
-                self.inner = Some(Arc::new(deserialize(s.as_bytes()).unwrap()));
+                let deser: Option<sasca::FactorGraph> = deserialize(s.as_bytes()).unwrap();
+                self.inner = deser.map(Arc::new);
                 Ok(())
             }
             Err(e) => Err(e),
diff --git a/tests/test_factorgraph.py b/tests/test_factorgraph.py
index 1d47e7ef..5fe8f948 100644
--- a/tests/test_factorgraph.py
+++ b/tests/test_factorgraph.py
@@ -13,6 +13,37 @@ def make_distri(nc, n):
     return normalize_distr(np.random.randint(1, 10000000, (n, nc)).astype(np.float64))
 
 
+def test_copy_fg():
+    graph = """
+        NC 2
+        PROPERTY s1: x = a^b
+        VAR MULTI x
+        VAR MULTI a
+        VAR MULTI b
+        """
+    graph = FactorGraph(graph)
+    graph2 = copy.deepcopy(graph)
+
+
+def test_copy_bp():
+    graph = """
+        NC 2
+        PROPERTY s1: x = a^b
+        VAR MULTI x
+        VAR MULTI a
+        VAR MULTI b
+        """
+    graph = FactorGraph(graph)
+    n = 5
+    bp_state = BPState(graph, n)
+    distri_a = make_distri(2, 5)
+    distri_b = make_distri(2, 5)
+    bp_state.set_evidence("a", distri_a)
+    bp_state.set_evidence("b", distri_b)
+    bp_state.bp_loopy(1, initialize_states=True)
+    bp_state2 = copy.deepcopy(bp_state)
+
+
 def test_table():
     """
     Test Table lookup