diff --git a/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attester_slashing.py b/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attester_slashing.py
index c51f5a8a9..2d8f9d31a 100644
--- a/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attester_slashing.py
+++ b/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attester_slashing.py
@@ -142,12 +142,39 @@ def test_participants_already_slashed(spec, state):
 
 @with_all_phases
 @spec_state_test
-def test_custody_bit_0_and_1(spec, state):
+def test_custody_bit_0_and_1_intersect(spec, state):
     attester_slashing = get_valid_attester_slashing(spec, state, signed_1=False, signed_2=True)
 
-    attester_slashing.attestation_1.custody_bit_1_indices = (
-        attester_slashing.attestation_1.custody_bit_0_indices
+    attester_slashing.attestation_1.custody_bit_1_indices.append(
+        attester_slashing.attestation_1.custody_bit_0_indices[0]
     )
+
     sign_indexed_attestation(spec, state, attester_slashing.attestation_1)
 
     yield from run_attester_slashing_processing(spec, state, attester_slashing, False)
+
+
+@with_all_phases
+@spec_state_test
+def test_attester_slashing_invalid_att_1(spec, state):
+    attester_slashing = get_valid_attester_slashing(spec, state, signed_1=False, signed_2=True)
+
+    indices = attester_slashing.attestation_1.custody_bit_0_indices
+    assert len(indices) >= 3
+    indices[1], indices[2] = indices[2], indices[1]  # unsort second and third index
+    sign_indexed_attestation(spec, state, attester_slashing.attestation_1)
+
+    yield from run_attester_slashing_processing(spec, state, attester_slashing, False)
+
+
+@with_all_phases
+@spec_state_test
+def test_attester_slashing_invalid_att_2(spec, state):
+    attester_slashing = get_valid_attester_slashing(spec, state, signed_1=True, signed_2=False)
+
+    indices = attester_slashing.attestation_2.custody_bit_0_indices
+    assert len(indices) >= 3
+    indices[1], indices[2] = indices[2], indices[1]  # unsort second and third index
+    sign_indexed_attestation(spec, state, attester_slashing.attestation_2)
+
+    yield from run_attester_slashing_processing(spec, state, attester_slashing, False)