Keith Slater was stabbed in the neck on his own doorstep
A 52-year-old man has been arrested in Northumberland in connection with the murder of a man more than 20 years ago.
Keith Slater, 35, was found stabbed at his home in Hessle, East Yorkshire, in August 1988. A man is already serving a life sentence for his murder.
Police arrested a man in Widdrington on Wednesday on suspicion of conspiracy to commit murder and soliciting another person to commit murder.
A police spokesman said he remained in custody on Thursday.
Officers have appealed for anyone with information to contact them.
Driving instructor Mr Slater was knifed in the neck on his doorstep in Bon Accord Road on 27 August.
'Others were involved'
A reconstruction of the murder, shown on the BBC's Crimewatch, led police to Martin Brown.
He had fled to Australia and was tracked down by Humberside Police using new DNA technology and extradited in 2004.
Brown was jailed for life in 2007 at Sheffield Crown Court, and ordered to serve at least 13 years.
Martin Brown started a new life in Australia after the killing
But Ch Supt Colin Andrews, of Humberside Police, said: "It's always been our view that there was more than one person involved in Keith's death.
"We believe that there are still some people out there who know about this crime and my appeal is for them to come forward and talk to us.
"Despite the fact that we have one man convicted this is still very much a live murder investigation and I think people have information they can give us which can help us get to the truth about this murder."
Mr Andrews added: "We will not close this inquiry until I am satisfied that we have caught everybody responsible."
He said the arrested man was living in the south of England at the time of Mr Slater's death but had previously lived in Willerby near Hull.
He was interviewed by police in 1988 but there was not enough evidence to link him with the crime.