Dayana Francisquini told her husband she could not breathe
Questions are being raised about the design of a south London block of flats after a fire which killed six people.
Officials are examining escape routes and fire prevention measures at the 12-storey Lakanal House in Camberwell.
The area's MP, Harriet Harman, said people were "asking questions" about the safety of the building, which has a single central staircase.
Fire officers said that while the building design was common, the rapid way the fire had spread was unusual.
The victims have been named as Helen Udoaka, 34, and her three-week-old daughter Michelle, Dayana Francisquini, 26, Filipe Francisquini, three, and Catherine Hickman, 31.
The sixth victim, who has not been formally identified, is believed to be Ms Francisquini's young daughter, named in media reports as Thais.
Three-week-old Michelle Udoaka was the youngest victim of the fire
A firefighter remains in hospital, though police said his condition was not thought to be serious.
'Locked' in bathroom
Ms Harman said there would "have to be a thorough investigation into what caused this fire and whether the prevention was adequate".
"There are many blocks with one central stairwell and questions will have to be asked about what happens when a fire breaks out," she said.
One of the victims, Dayana Francisquini, had locked herself and her two children in their bathroom in a bid to survive, her husband Rafael Cervi, 31, told the Sunday Telegraph.
The hotel porter from Brazil was at work when he heard the building was on fire.
Catherine Hickman was one of six victims of the tower block fire
He said the last words he heard from his wife were in a phone call during the blaze when she told him: "I can't breathe very well. I'm struggling to breathe and Filipe's really scared."
Mr Cervi told the newspaper: "They were what I lived for. Now everything is gone and I have nothing."
Tower blocks such as Lakanal House had been designed so that fire did not rapidly spread, said Brian Coleman, chairman of the London Fire and Emergency Planning Authority.
"In buildings such as this one you should be safe for an hour before fire jumps from floor to floor," he told Sky News.
"That wasn't the case in these circumstances and I think we need to know why the fire spread so quickly and jumped between floors in such a short space of time."
Onlookers had reported seeing people trapped inside shouting for help.
And one resident said the layout of the maisonettes was like "a maze" - making evacuation difficult.
Harriet Harman: "There will be a full investigation"
The Metropolitan Police said the fire began in a flat on the ninth floor, but that all those who died were on the 11th floor, with other floors also affected.
"It's a very complex, very large inquiry," Chief Supt Wayne Chance said.
London mayor Boris Johnson described the fire on the Sceaux Gardens Estate as a "horrendous incident".
"It does seem suspicious that the fire was spreading so quickly and clearly that will be one of the prime subjects for the investigation," he said.
"Obviously we will want to know whether... the fire was set, whether there was any malign intent."
There would also be an investigation into whether there were any "design failures" in the building, he said.
About 30 people had to be rescued from the building as the fire spread. Another 120 were evacuated.
London Fire Brigade (LFB) assistant commissioner Nick Collins said it was "one of the most significant fires in some time in terms of lives lost".
More than 100 firefighters tackled the incident, some of who suffered from heat exhaustion, he added.
Eyewitness footage of Camberwell fire
Resident Carol Cooper, 38, who lives on the seventh floor, described "seeing people and children waving for help".
She added that the tenants had called for the block to be demolished two or three years ago - but had been told it was a listed building, and had to be preserved.
Southwark council's executive member for housing, Kim Humphries, said the tower block had undergone a £3m refurbishment programme two years ago.
This is understood to have included fitting new windows and electrical cabling.