William Jones had been looking for his former girlfriend and her new partner when he kicked the door of Mr Lewis' flat in Claude Road, in the Roath area of Cardiff, in the early hours of 28 April 2012.
Mr Lewis came to the front door and was stabbed, later dying of his injuries in hospital. The pensioner had a learning difficulty and a number of physical impairments, including blindness in one eye and arthritis.
More top news
Tributes have been paid after two Matalan employees were allegedly stabbed to death near the city centre store where they worked.
A damp start to the night with heavy rain spreading southwards. It will clear by the early hours to leave a dry start tomorrow.
A mother of two has told ITV Wales she's saving money to buy life extending cancer drugs as she anticipates the NHS won't fund them.