THE disappearance of Louise Tiffney remains a mystery after her son was cleared of her murder yesterday.

Ms Tiffney's family and the police remain convinced she is dead. But without the discovery of a body it is impossible to say what has happened to her since she was last seen almost three years ago.

Sean Flynn, her son, said yesterday: "I sure as hell didn't kill her, " and the jury's not proven verdict raises the alternatives that she was murdered by someone else or perhaps killed herself. It also remains possible that she is still alive, creating a new life for herself.

Mr Flynn insisted after the case: "I didn't kill my mum. I just had an argument with her like I said in court, and then she walked out. I want them all to know that this has all been a lot of nonsense."

June Tiffney, speaking on behalf of the family, said the verdict was "not justice" and accused the jury of failing to use common sense.

She said: "This is not justice for Louise. She is dead and there's no doubt about that.

Her name has been dragged through the mud by her own son and his father, but we know, and they know, the truth.

"Sean has robbed his sister of his mother and ruined our lives.

The jury had all the facts - where was the common sense?"

Detectives were baffled when Ms Tiffney vanished without trace on the night of May 27 2002 without taking any cash, bank cards, clothes, or her passport.

The 43-year-old single mother of two from Edinburgh went missing in the week Mr Flynn was due to stand trial for causing the deaths of his cousin, Paul Ross, and best friend by dangerous driving. Mr Flynn was later jailed for nearly four years over the fatal high-speed crash in West Lothian in January 2001.

Riddled with anguish over the crash, Ms Tiffney at one stage said she believed it would have been easier if Sean, and not Paul, had perished in the wreckage.

Relatives initially feared the stress of her son's court case had taken its toll. Her family, including daughter Hannah, six, made an emotional appeal for Ms Tiffney to come home.

But soon the spotlight of suspicion began to turn towards Mr Flynn, now 21, and the only member of her family who seemed strangely unconcerned by her disappearance. A picture also emerged of constant rows with his mother.

She was described as both a fantasist and a doting mother who used her only daughter as an emotional crutch when she thought she was losing her son.

She was also deeply affected by the relationship her son had with a woman older than her, Yvonne Solo.

Ms Tiffney's life was said to have been a troubled and unfulfilled one. At times hilarious and chatty, she also suffered from a lifelong battle with depression. Born Wilma Jane Isobel Tiffney in Edinburgh in 1959, she was the second oldest of Roger and Mary Tiffney's five daughters.

Her problems with depression first appeared when she was a teenager and her weight dropped to six stone as she struggled to cope with the eating disorder anorexia.

She moved out of the family home when she was 17 and into a flat with a male friend, changing her given name of Wilma to Louise shortly afterwards.

Mr Flynn's grandmother, Mary Tiffney, 72, said her daughter was energetic, humourous, and witty and devoted to her family, but that Ms Tiffney's relationship with her son had deteriorated over the months leading up to her disappearance.

One former colleague said:

"She was a live-wire. She always had something on the go, and she was fun to have around. Some folk thought she was a bit scatty."

However, Frances McMenamin, defence QC, said that rather than resembling a doting mother, Ms Tiffney seemed much more like a "troubled, extravagant, volatile, impulsive, needy and very selfish person whose family and children are all there as mere crutches to help her get through every night and day".

She had been facing spiralling debts and had considered accepting a sham marriage or prostitution to solve her money worries. But when she borrowed - pounds7000 from her elderly mother, Mary, instead of paying off the debts, she spent the money on a new bathroom and beauty treatment.

The High Court heard on the day she vanished, Mr Flynn told his father, taxi driver Keith, 50, that his mother was "f***ing up" his life.

When Mr Flynn stormed out in a rage after his mother accidentally broke a toy car while tidying his room, Ms Tiffney sent him a poignant note. She wrote: "I miss having you about the house. I just miss life as it used to be. I love you very much. Mum."

Questioned by police, Mr Flynn said his mother had walked out of their flat in Dean Path during a row on the night of her disappearance. He denied murdering Ms Tiffney and dumping her body at an unknown location.

He insisted a piercing shriek neighbours heard that evening was a noise his mother often made when upset.

What had started as a routine missing person inquiry on Tuesday May 28 2002 had turned into something more sinister by June 28 when, on the hunch of a detective, the Nissan Almera used by Mr Flynn was checked for blood and it was more than a billion to one chance that it was not Ms Tiffney's.

By then police divers had searched the Water of Leith, posters of Louise had been distributed and police believed she had not simply walked away from her family. What followed was an investigation of breathtaking scope.

Checks were made with the Benefits Agency, the Job Centre, the Inland Revenue, and the National Insurance unit, but nothing was found. She had made no effort to change her name, or get a driving licence, or a new passport.

All 28 bank and 64 building society chains across the country were checked. She had not touched nearly - pounds400 which was in her Abbey account when she went missing.

Despite Ms Tiffney's body never being found, Scots law allows for a person to be charged with murder. The legal precedent was set in 2003 when businessman Nat Fraser was convicted of the murder of his wife, Arlene. The mother-oftwo, from Elgin, Moray, vanished from her home in 1998.

CCTV footage was recovered from bank cash machines and one in Wolsely Place appeared to show a car like Mr Flynn's heading east out of Edinburgh at 1.20am, and back into the city at 2.31am.

Huge swathes of woodland, mine shafts and the shore at North Berwick were scoured by teams of up to 80 officers at a time.

Lothian and Borders police said officers were convinced Ms Tiffney was dead, despite never finding her body. A spokesman said: "We carried out a full and thorough investigation and presented our findings to the procurator-fiscal. It is the jury's duty to decide the verdict on the evidence.

"It is inappropriate to comment further."