Police have named the man as Thomas Baird. He'd been stabbed and was pronounced dead in the early hours of Saturday after the blaze at his home in Westerdale, Hemel Hempstead, Hertfordshire.
A post-mortem examination carried out yesterday concluded that the 63-year-old died of trauma to the head and neck, and stab wounds to the chest.
A 30-year-old man from Hemel Hempstead, who was arrested on suspicion of murder on Saturday, remains in police custody.
More top news
A woman who sparked a hate campaign against an ex-boyfriend and the women he dated has been jailed for stalking.
Surrey Police say they are working through more than 100 calls over reports a boy was 'abducted and bundled into van' in Redhill in Surrey.
Police have made a breakthrough in rape investigation using DNA and CCTV footage.