DCI Keith Hardie was speaking after remains found at Gosford House, Longniddry, were identified by dental records as the missing mother-of-two.
The 43-year-old laundrette worker vanished from her Dean Village home 15 years ago next month.
DCI Hardie said he had spoken to Louise’s sisters, June Tiffney and Iris McKinlay, personally and that they were “relieved” at the news.
“From speaking to the sisters, I think they’d given up hope of finding Louise alive,” he added.
“So rather than this being bad news, it may even be considered good news for them because they might be able to bring this lengthy, lengthy event to some kind of conclusion.”
Up to 40 officers have been working on the case and DCI Hardie said they would leave no stone unturned in trying to piece together Louise’s last moments.
“That’s what we do, we deal with homicides and investigate homicides,” he said. “This happens to be a 15-year-old homicide but it matters nonetheless.
“We’ll be 100 per cent
committed to trying to identify the person responsible for Louise Tiffney’s murder.”
DCI Hardie refused to be drawn on whether Louise’s remains, found by a cyclist on Sunday, had given up any clues as to how she died.
“It’s far, far too early,” he said. “You have to understand we’re still in the process of recovering the remains themselves today.
“Once we get them in sterile conditions and start reviewing them obviously we’ll look at a potential cause of death but that’s far further down the line.”
A former senior detective in Edinburgh told the Evening News an incident room would be set up and all the old files on Louise’s disappearance re-examined.
“The case has never been closed down but an incident room will be reactivated and they’ll pull out all the old files on the case,” he said.
“The main thing they’ve got to go on is forensics to try and find a cause of death. It’s been done before and you never know, DNA could be recovered.”
Police being able to identify Louise through her dental records is “good news” as it suggests no effort was made to conceal her identity and her killer was “in a hurry”, he added.
Police are still treating the case as a murder inquiry and will be trying to piece together her last moments while carrying out DNA tests.
Officers will now work with the Crown and Procurator Fiscal in trying to uncover the circumstances around Louise’s death.
Louise was last seen leaving her home in Dean Path on May 27, 2002. Her family always believed she was killed and her body buried at Gosford.
Her son, Sean Flynn, then 21, was charged with her murder in 2005 but walked free after a not proven verdict.
DCI Hardie said there was “no reason” to speak to Mr Flynn, who is believed to have moved from Scotland, or anyone else, at this stage.
“My job as senior investigating officer at this point is to ensure we maximise every potential forensic evidential opportunity around the recovery and the site where she was discovered,” he added.
“That will remain our focus and priority and it’s still very much being treated as a murder inquiry.”
Louise’s remains were in a “skeletal state” and found in a “very, very secluded area” about eight metres from the A198 with no reason for anyone to be there, said DCI Hardie.
The Evening News reported on Wednesday how police had drafted in a world-renowned forensic team from Dundee University to help the inquiry.
Police searched Gosford back in 2002 but DCI Hardie refused to say yesterday how close they came to where Louise was found.
“It doesn’t really interest me how close we came last time because we never found her, we’ve found her now and we have to maximise the opportunities around that find,” he said.
Investigators are yet to pinpoint a time of death but are working on the assumption it was soon after Louise disappeared.
“The time of death will be around the time she went missing, I would guess,” said DCI Hardie. “We’ve employed experts to give us an idea around times but I would think it’ll be very difficult. She hasn’t been seen for 15 years.”
DCI Hardie thanked a “handful” of people that had contacted the inquiry team after news of the find first broke on Monday.
“This case has been subject to a significant amount of media speculation and on the back of that people have phoned up with information they suspect might be of use to us,” he said.
“We’re more than happy to speak to them. As far as anything else around who’s responsible, it’s far, far too early.”