A woman from Brighton has said she fears her brother's killer could be heading to her home after he escaped from prison.
Police said Ryder has associates in the south east
Diana Cole said Mark Ryder, 37, mouthed "you're next" to her as he was led away to begin his life sentence in 1993.
He escaped from Highpoint Prison, Suffolk, during an escorted trip to Cambridge on 12 October.
Ryder was sentenced to 15 years for murder after he shot dead love rival Stuart McCue.
Det Sgt Laurence Cartwright, of Sussex Police, said people should be wary that Ryder might return.
"Certainly if they see him or hear of his whereabouts then they should let us know.
"It's something they should be aware of but not overly concerned about at this stage," he said.
Ryder was sentenced to 15 years for murder after he shot dead Mr McCue when he went on the run from guards in Brighton while serving a sentence for theft.
A prison service spokeswoman said "This is not an escape or an abscond, it is classed as a failure to return. An internal inquiry into this incident is already underway."
Ms Cole, who lives in Brighton, said the last few days had been "absolute hell".
She added: "I can't sleep. None of the family can. I'm scared. These nightmares have brought it all back again."
A spokesman for Sussex Police added that they acknowledged Ryder did have friends and associates in the south east.
"All officers have been briefed about his escape and his picture circulated."
He said an investigation had begun focusing on identifying people who may be at risk from Ryder and taking measures to reduce that danger.
"It must be stressed that there have been no sightings of Ryder in the Brighton area."
Ryder is described as white, 5ft 5in, with mousey, brown hair which is shaved and greying at the sides.
He has a faded tattoo of a cross on his forehead and 'Love' tattooed on his left hand knuckles and 'Hate' on his right.
Ryder also has a tattoo on his left arm of a dagger through a skull and crossbones with a scroll stating 'All or Nothing Anna'
Anyone with information should contact police.