A three-year-old girl has survived a "targeted" shooting at a house that left three dead and two injured.
A car sped off after the shootings, one neighbour said
Hertfordshire police were called to an incident at a house in Plaw Hatch Close, Bishop's Stortford, on Tuesday.
Two men, aged 33 and 52, and a 17-year-old boy died at the scene. Two women, aged 23 and 54, were injured.
They are in a critical but stable condition in hospital. The girl was found in the house unharmed. Police have begun a murder inquiry.
Police are looking for two slim Asian men in connection with the attack.
The pair were seen making off from the scene in a small red car, and were described by police as being aged in their late teens or early 20s.
'Sense of shock'
Officers have been conducting a full investigation of the scene.
Ch Supt Al Thomas, of Herts Police, said: "We don't underestimate the impact of these murders.
"We share the concern and sense of shock within the community.
"Early information suggests this was a targeted incident and not a random attack, we have no information to suggest this is part of a trend or escalation in gun crime in the county."
Witnesses at the scene said a father and son had been killed in the attack, but police have not yet released the identities of the victims or their relationships.
House-to-house inquires were being carried out and a forensic search of the area under way.
A neighbour, Richard Guy, told BBC News: "I came back from the pub about twelve o'clock and, yeah, there was police here.
"I mean, before I went out I heard a bang and a car speed off quite quickly but it's something that I hear round here quite regularly so I didn't really expect it to be anything, anything bad.
"I've only been here since December. For something to this extent to happen already - it's quite a shock to everyone I think."
Dean O'Connell, who also lives in the close, said: "You don't expect it somewhere like this, but this estate is renowned for a little bit of drugs - most of the trouble here, I imagine, is because of drugs."