The murders of two women found strangled and burned in their flats in Hasting 11 years ago are being reinvestigated.
The bodies of Clare Letchford, 40, and 70-year-old Beryl O'Connor, known as Dornie, were discovered in their homes which were less than 100 yards apart in January 1998.
Now, Sussex Police's major crime branch have reopened the case, and are linking the deaths to an attempted murder which happened the same month.
They are questioning one 35-year-old man over all three attacks, and have arrested another man in connection with the pensioner's murder.
Four people were arrested at around the time of their deaths but no charges were brought.
The attempted murder, which is being investigated by British Transport Police (BTP) involves an attack on a 19-year-old Czech student on a Hastings to London train.
The 46-year-old man, from Northern Ireland has been released on police bail.
The women's deaths shocked Hastings after the two bodies were discovered within days of each other in 1998.
Their inquest heard the killer strangled Mrs O'Connor and attempted to strangle Mrs Letchford before setting their bodies on fire, using their clothes to fuel the flames.
Mrs Letchford was found dead at her rented basement flat in Cornwallis Gardens, where she lived alone, on January 18, 1998.
Mrs O'Connor was discovered at her home eight days later.
Home Office pathologist Iain West said Mrs Letchford was found badly burned with a pair of shoelaces tied around her neck and a cushion cover over her head.
He said she had been restrained before being set alight and died from inhaling smoke
Police said the investigation into the murders was complex and wide-ranging but that the Crown Prosecution Service (CPS) would be passed details of their "significant progress" shortly.
Detective Chief Inspector Trevor Bowles, of Sussex Police, said today: "This investigation is over 11 years old but it still resonates in the thoughts and concerns of the people in Hastings.
"The re-investigation of the murders of Claire and Dornie is complex and wide-ranging. We will shortly be speaking with the Crown Prosecution Service about the significant and exciting progress we have made."
The attack on the Czech student happened on January 26, 1998, when she was raped and viciously attacked in a toilet just three months after she arrived in East Sussex as an English language student.
Detective Chief Inspector Alistair Cumming, of the BTP, said: "Despite the passage of time, the resolve of British Transport Police to detect this dreadful attack on an innocent train passenger has never diminished.
"It is comforting to the Czech victim that the matter is now being passed to the Crown Prosecution Service."
All three cases featured on the BBC's Crimewatch programme.
The Czech victim, who has since returned to her homeland, was found by a train guard, covered in blood and with severe head injuries, and is said to still suffer as a result of the ordeal.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article