Lewis S03E03 - The Point of Vanishing

Steven Mullan, a former religious maniac who served time for running atheist writer Tom Rattenbury off the road, crippling Tom's daughter Jessica in the process, is murdered. Or rather his flatmate, who swapped identities with him to escape the wrath of his lover's husband, is. Then the real Steven Mullan is killed and Tom commits suicide, claiming he killed both lads. But Tom had an alibi and Jessica and Steven were closer than anybody guessed. Who has engineered the cover-up?