A 52-year-old woman was left with a fractured skull and other facial injuries after an alleged assault in her home in Lincoln.
Police and paramedics were called to the house on Moorland Avenue on February 10 at just after 5pm.
The woman was taken to Lincoln County Hospital and was discharged on March 3.
A 46-year-old man was arrested the following day on suspicion of committing grievous bodily harm.
He was later released on police bail to return to the police station after further investigation.
Detective Inspector Suzanne Davies of Lincoln CID said: “This was a serious assault, thankfully the victim has since been discharged from hospital.
“Whilst our enquiries are well advanced I would still appeal for anyone who has any information about the incident to contact me via the 101 non-emergency number or anonymously through Crimestoppers on 0800 555111.”