Keith Cowell, 52, and his son Matthew, 17, were shot dead at their home in Bishop's Stortford, Herts, on August 28, along with Tony Dulieu, 33, of Billericay, Essex.

Kevan Thakrar, 20, of Lomond Way, Stevenage, appeared before Stevenage magistrates' court facing three counts of murder, two of attempted murder and a firearms offence. His father, Atul Thakrar, 46, of the same address, is charged with one offence of assisting an offender.

Magistrates refused an application for bail and both men were remanded in custody until September 21 when they will be brought before St Albans Crown Court.

A 23-year-old woman and a 54-year-old woman were badly hurt in the attack at the semi-detached house in Plaw Hatch Close. They are said to be in a "serious but stable" condition in hospital, where they are thought to be under police guard.

Locals named the younger woman as Clare, Matthew Cowell's girlfriend. The older woman was said to be Keith Cowell's sister, Christine.

Police said a three-year-old girl, named by neighbours as Clare's daughter Courtney, was unharmed and is being cared for by family members.

An unidentified third man charged with dealing class A drugs in connection with the murder investigation appeared before magistrates on Wednesday, police said. His identity is being withheld "to protect the integrity of the case", a Hertfordshire Police spokeswoman said.

For "operational reasons", the case was heard in closed session at an unnamed court, she added. She would not confirm if a man in his 30s arrested in London on Monday was the third person charged.

Two men arrested in Stevenage last Friday in connection with the murders have been released on police bail pending further inquiries.