A murder probe is under way after tests showed a man died of multiple fractures.
The body of Steven May, 50, was discovered at an address in Raven Street, Preston, after police were called at about 9.45am on Monday.
A post-mortem examination revealed a number of injuries to Mr May's body including multiple fractures.
Police say it is thought he died as a result of the fractures.
A 44-year-old man from Preston has been arrested on suspicion of murder.
Detectives want to speak to anyone who may have seen or heard from Mr May in the days leading up to his death.
Detective Inspector Martin Pearson, from Preston Police, said: "Firstly, my thoughts are with Steven's family and friends at this extremely sad and distressing time.
"We have specially trained officers offering them support.
"We are looking at his last movements in the time before he suddenly died to try and build a picture of what has happened to him and why.
"If you think you saw him, please make contact with us as you may have vital information to assist our investigation.
"Similarly if you know anything about how Steven could have come about these fatal injuries, please come forward."
Anyone with information should call 101, quoting incident reference 1596 of May 23.
Alternatively, contact Crimestoppers anonymously on 0800 555 111 or online at crimestoppers-uk.org.
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