It is understood that police are not looking for anyone else in connection with the deaths of three people at a house in north-west London.
Ambulance services confirmed that a woman and two children were found dead at the scene.
A spokeswoman for London Ambulance Service said: "We were called at 6.40pm to reports of an incident in Midcroft, Ruislip. We sent three ambulance crews, two single responders in a car, two officers and our hazardous area response team.
"Sadly three patients, a woman and two children, were dead at the scene."
More top news
Launching Plaid Cymru's campaign, leader Leanne Wood, says the general election offers Wales an "unprecedented opportunity" for change.
A woman who sent £1,000 to her jihadi boyfriend in Syria before he dumped her has avoided a prison sentence today
Ed Miliband has launched Labour's General Election campaign with the promise of a "double lock" to safeguard the future of the NHS.