A man has been arrested on suspicion of murder after the bodies of a woman and two children were discovered in the former home of John Lennon.
Merseyside Police launched an investigation after being called to a ground-floor flat in Falkner Street, Toxteth, at around 7.30pm on Tuesday after concern for the safety of the occupants.
Officers said the investigation was in its early stages, but believe it is "domestic related".
Neighbours said the property was regularly visited by Beatles fans on tours of the city as the band's manager Brian Epstein had owned a flat there, where Lennon lived with his first wife Cynthia shortly after they married.
One man, who did not want to be named, said: "The tourist tours are always stopping at the house because John Lennon used to live there."
He said a family with two young children had lived in the flat.
He said: "I didn't know them, I just knew there was a family living there. The children were toddler age."
Residents on the street were evacuated from their homes at about 7.30pm on Tuesday due to concerns over a gas leak.
One woman said: "The police said we had a couple of minutes to get out of the house.
"There were ambulances, fire engines and police here. We weren't allowed back in until about 11pm."
On Wednesday morning, a police cordon remained in place outside the terraced house.
Police have said they are not looking for anyone else in connection with the deaths at this stage.
The 30-year-old man was arrested and then taken to hospital after falling ill.
The force said a post mortem will be carried out.
Anyone with information is asked to call police on 0151 777 4065 or Crimestoppers anonymously on 0800 555 111.