IT WAS a tale that could have been the making of a script for a horror film.

A carer and her client found dead in a flat, sexually assaulted with their bodies tied up and their killer on the run. But the reality was a situation facing detectives embarking on one of the most high-profile murder cases of last year.

For the man charged with leading the investigation, it was the start of long days and sleepless nights until the man they were hunting was found and put in jail.

When Sarah Merritt and her disabled client Susan Hale were found dead it was detective chief inspector Jason Hogg who took the call and became the senior investigating officer (SIO).

Recalling the phone call he said: "We had a carer who had not been seen all day, her car found outside a property in Townhill Park, police had forced entry and two bodies had been found inside tied up.

"At this point nobody has had a good look around the scene. The officers have literally been in, checked both people were not alive and then got out to protect the scene.

"Very quickly we needed more information from the crime scene and forensics were sent in. We needed to establish who they were, what weapons had been used, an indication of who has done it and if there are any clues to who the killer could be."

DCI Hogg, 33, said: "I never go in to a crime scene, but it's a matter of choice. I feel I don't need to be there. With technology I can now see everything on a disc on computer in a matter of minutes.

"Immediately there was background work done on the address. We had a suspect from the start - David Tiley - and very quickly found out he was a sex offender managed by Hampshire Constabulary. We had a lot of information from the beginning which cannot always be the case when you are told of a murder.

"Friends, relatives and acquaintances of the deceased were all contacted and we were able to establish Tiley had not contacted them. At that moment we had no idea where he was." said DCI Hogg, who works in the county's Major Crime Department and has been in Hampshire since 2001.

The following morning as news of the dreadful events of the double killing made local and national headlines, DCI Hogg and his team of detectives continued trying to hunt down Tiley. Amongst all the pressures of trying to capture a dangerous killer, there was also mounting pressure from the media wanting to know who did it and where he was. Divulging details to the general public was a carefully made decision, said DCI Hogg.

"Publishing Tiley's picture was a decision I had to make, balanced against the fear that if he knew we were looking he may be encouraged to change his appearance and his clothing.

"There was also a risk that by releasing his identity we could be flooded with calls of sightings all over the country and that would take away our resources.

"Initially, by doing a number of checks, we were happy that we were on his trail so we made the decision not to publish his picture. We had every one of the 140,000 police officers in the country looking for him, but as time went on I felt it time to release it."

Behind the scenes a specialist "casualty bureau" was set up - on this occasion in Basingstoke.

"We have this on all major running jobs. It's a stand alone control room with a dedicated number staffed by people who know the job and know what information is necessary. On this occasion a number of calls were received from members of the public."

His picture circulated across the country, in the end it was a WPC in Dorset who spotted the killer and arrested him on Saturday morning - but for DCI Hogg and his team, despite the immense relief, the hard work had only just begun.

"It can be extremely tiring, especially in the early stages. In my opinion if I get to the stage when I'm feeling really tired then I'm not making good decisions and I will go home.

There are never any quiet periods - if there are enquirywise then there is always the media on your back for updates. Sometimes you don't and can't go to sleep but by and large you are so exhausted you do. It's so important to know when to let go and try and switch off.

"Catching the killer is just the first stage of a murder enquiry. You have to be thinking all the time about what you have that can be put in front of a jury in order to convict.

"For me the job is not just about catching them but also putting them away for a long time. It's a team effort and it's down to the whole team on any murder case when we get a successful outcome at court."