A fourth person has been arrested on suspicion of murdering an 89-year-old man in Blackburn.
Albert Fielding was found dead by police after a neighbour raised the alarm at Limefield Court, off Preston New Road, on Friday morning.
A post-mortem examination found he died of head injuries.
Police arrested a 23-year-old man from Chorley on Saturday night. Two men, 39 and 46, and a woman, 45, all from Blackburn, were arrested on Friday.
Lancashire Police are continuing to appeal to anyone with any information to contact them.