Between the Lines S02E02 - Manslaughter

Det. Supt. Lindsay has confessed to killing his wife, claiming he did so as a crime of passion; however Clark is sceptical. His suspicions are aroused because of similarities to a case Lindsay investigated five years ago, and as time is running out, he is under pressure to get the right result. It is discovered that Lindsay had been having an affair with his sister-in law, and the post-mortem uncovers crucial evidence.