Kevan Thakrar, left, and brother Miran were convicted of three murders
Two brothers jailed for three machine gun murders will not attend an appeal hearing following security concerns, a Court of Appeal judge has ruled.
Miran Thakrar, 24, and Kevan Thakrar, 21, are to appeal against their convictions, for which they both received life terms.
Drug dealers Keith Cowell, his son Matthew, and Tony Dulieu, from Essex, were gunned down in Herts in 2007.
A judge said a video link from prison would be appropriate.
The Thakrars were jailed for at least 42 years and 35 years respectively in 2008.
They had denied three counts of murder and were convicted following a trial at St Albans Crown Court.
Anger about drugs
Lawyers for the brothers asked Lord Justice Stanley Burnton to direct that they be brought to London to watch their appeal take place.
He agreed with security concerns raised by the prosecution and ruled that they should not attend.
The prosecution case at the brothers' trial alleged that they had gone to the Cowells' house in Bishop's Stortford for a cocaine deal, but Miran Thakrar was angry about the quality of the Cowells' drugs sold in the past.
He shot the family dog, then lined up Keith Cowell, 52, 17-year-old Matthew Cowell and 33-year-old Mr Dulieu and shot them dead with a Mac 10 sub-machine gun as his brother watched, the crown court heard.
The prosecution also alleged small-time dealer Miran fled to Turkish north Cyprus following the murders, described as "cold-blooded" and "savage" by the trial judge.
Lawyers for the brothers revealed to the Court of Appeal that a trio of witnesses, whose evidence is pivotal in the appeal, may refuse to come to the UK.
Lord Justice Burnton said all attempts should be made to get the witnesses to court, but that a video link with Cyprus would be a viable alternative.
The three-day appeal, in which Yilay Tufensoy, of Enfield, north London, will also challenge his conviction for assisting an offender, is due to be heard later in the summer.