A woman being stalked by her former partner secretly filmed him breaking into her home and snooping around.
Debbie Phillips was stalked by her ex-partner
Photographs and underwear were going missing from Debbie Phillips' south Wales home, and she did not at first realise the father of her two children had stolen a house key.
She is one of an increasing number of people who fall victim to stalkers.
She spoke to BBC Wales' Week in Week Out, which discovered that stalking is one of the UK's fastest-growing crimes.
More than 2m people claim they have been victims in a 12-month period.
The programme investigates the problem and asks what more can be done to combat it.
The official government figure for stalking incidents for 2001 was more than double the number of burglaries in the same year.
And experts believe the real numbers could be much higher as many cases of stalking go unreported.
Week in Week Out speaks to some of the victims, including Ms Phillips, who is shown watching CCTV footage of her former partner breaking into her home in Porth in Rhondda, south Wales after their relationship ended.
"When you find out you just can't believe it," she tells the programme.
Mark Bradfield was filmed breaking into his ex-partner's house
"It sort of hits you, and you can't stop shaking because ... it's like a horror film or a thriller. You never thought in a million years it would happen to you.
"You don't think anybody sane would be doing these things."
Ms Phillips had feared for months that she was being watched by Mark Bradfield. She changed the locks, but said photographs and underwear were going missing, and he seemed to know about almost every aspect of her personal life
She filmed her ex-partner snooping around her home and reported him to the police.
Mr Bradfield was convicted in July on burglary, harassment and criminal damage charges.
"If I knew now what I should have known then, I wouldn't have done what I done, " Mr Bradfield tells the programme.
"I didn't think I was harming them in any way by keeping an eye on proceedings."
According to the British crime survey, only around 30% of those who said they were stalked told the police.
One of the UK's leading anti-stalking experts is Hamish Brown, a former policeman with 30 years experience in the Metropolitan Police, who now advises on combatting harrassment.
He says more should be done to encourage victims to come forward and to detect the crime.
"There is still much more room to have more detailed training where people understand this very unusual part of law," said Mr Brown.
"This part of law where people do things which aren't a criminal offence. Sending presents, hanging around outside someone's house, that sort of thing.
"But it really wears someone down, and we've seen in some tragic cases, some awful results, so there should be much more understanding of this very difficult and sensitive crime we know is staking".
The programme also investigates the case of pregnant Caroline Evans who was shot dead in the west Wales village of Llangadog 20 months ago.
Wil Davies, a local farmer with no previous convictions, had stalked Ms Evans who was the landlady of the Red Lion pub, for months before killing her and himself.
Davies was receiving psychiatric care having previously attacked the landlady, and a report into his treatment by the mental health services is expected next month from Carmarthenshire Local Health Board.
The board has already said there are lessons to be learned from the case.
Week In Week Out is broadcast on BBC One Wales at 2235 BST on Tuesday.