A man has been arrested on suspicion of murder after the bodies of a woman and two children were discovered following "continuous female screams" at a former home of John Lennon.
Merseyside Police were 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".
The arrested man, 30, was taken to hospital but discharged on Wednesday afternoon.
He is being questioned by officers.
One neighbour described hearing "a scream like no other" coming from inside the home at around 7pm.
The man, who did not wish to be named, told the Press Association: "I heard screams - it was screams that make you sit up and go outside to see what's going on. It wasn't a scream of joy."
He added: "They were female screams and it was continuous, that's what made me go outside.
"It was a scream like no other. It will stay with me for a while, to be honest."
He described seeing one man being "rushed out" into an ambulance, shortly before police evacuated part of the street.
The property is regularly visited by Beatles fans on tours of the city because the band's manager, Brian Epstein, had owned a flat there, where Lennon lived with his first wife Cynthia shortly after they married.
Driver Jay Riley, 67, stopped outside the property while taking tourist David McGann, 35, from Melbourne, on The Beatles Fab Four taxi tour on Wednesday morning.
He said: "This is where John and Cynthia, his first wife, spent their honeymoon and this is where he wrote the song Do You Want To Know A Secret.
"The reason he wrote the song Do You Want To Know A Secret is because this was Brian Epstein's secret apartment.
"Brian Epstein was gay and up until 1967 in England it was illegal to be gay. This is why it was called his secret apartment."
One man said a family with two "toddler-age" children had lived in the flat.
Residents on the street were evacuated from their homes at about 7.30pm on Tuesday due to concerns over a gas leak.
Police have said they are not looking for anyone else in connection with the deaths at this stage.
The force said a post-mortem examination will be carried out and tests were being carried out on a substance located at the scene.
Forensics officers wearing gas masks were seen in the property on Wednesday morning.
A Toyota Yaris with a smashed passenger window, which had been parked in the street, was towed away from the area.