UP TO 1,000 hours of video footage collected.
Nine months of private detective work from a team of five investigators who even disguised themselves as foreign workers and pregnant women.
Numerous types of equipment, including closed-circuit cameras, long-distance video cameras and motion detectors, used.
The cost of the whole exercise - a five-figure sum.
But the private investigation firm of SecureGuard Security Services Co-operative Limited delivered the goods.
The detective work helped the case of its clients, the Novena church, in its defence against plaintiff Madam Amutha Valli Krishnan, in the now infamous 'exorcism' trial. The much-publicised civil suit between Madam Amutha, 53, and the church finally came to an end on Friday when Justice Lee Seiu Kin delivered his judgment.
The case had dragged on for more than four years. It stemmed from her allegation that two priests at the church, Father Jacob Ong and Father Simon Tan, and several churchgoers had performed an exorcism on her against her will for more than 21/2 hours on 10 Aug 2004.
Part of the plaintiff's claim was that she suffered post-traumatic stress disorder (PTSD) as a result of her experience in the church.
It not only affected her mentally but physically as well. She claimed that she was not able to live a normal life.
This included having difficulties going to the toilet alone, at times not having confidence to be independent, and needing assistance all the time.
She also had to make numerous visits to the hospital to be treated for her condition, which was worsening, she claimed.
But as Justice Lee observed in his written judgement: 'In contrast to the rather dire picture of the plaintiff... the defendants produced video evidence, taken by private investigators, of the plaintiff going about her domestic activities, going out to the temple dressed in brightly coloured dresses and even working out on the treadmill and various other exercise machines in the gym.'
Producing this video evidence was the challenge for the team from SecureGuard, led by chief investigator Gilbert De Silva, 48.
The former police officer turned marine investigator and consultant for private investigations played a key part in collecting the evidence.
It was the longest surveillance project he had ever engaged in.
There was a time at the start of the investigations when he stayed at his post, with his operatives changing duty, for three straight days and nights.
He said: 'It was 72 hours long but it was crucial at that point in time that we had the right person.
'We were still in the process of establishing her identity and I wanted to be there for confirmation.'
That was challenge number one - getting the right person. The breakthrough came when they spotted Madam Amutha with her 'sworn brother' Resham Singh.
'We knew about Resham Singh and seeing the two of them together confirmed it, and the case was on,' said Mr De Silva.
The next challenge was to determine whether she was indeed suffering physically - that she needed help all the time.
The first breakthrough came when the surveillance managed footage of her washing and hanging out her clothes without any assistance from 29 to 31 Dec 2006.
She also dressed up and went to the Dharma Muneeswaran Temple in Serangoon North from about 4pm to 8pm.
'She was perfectly normal, even going down on her knees to pray,' said the investigator.
And if 72 hours was his longest stint at getting the evidence, it took him only 30 minutes to establish the fact that she could exercise without a walking stick.
'It happened by chance. I was taking my wife to her school in Ang Mo Kio when I spotted Madam Amutha at Bishan Park.
'I handed the car over to my wife, took out my video cam and followed her. It was all over in 30 minutes but it showed that she could walk properly,' he said.
Then there was the time she was caught on tape at the gymnasium in Yio Chu Kang Sports Hall.
'She was lifting weights and running on a treadmill,' said Mr De Silva.
'But what was interesting was that she was doing it all on her own, and in a place with strangers. When she was on the treadmill, there was a man exercising next to her and she displayed no fear.'
While getting this footage proved to be crucial, it was also the start of a difficult period.
'My cameraman held the shot for one second too long and she noticed us,' he said.
Madam Amutha then became more difficult to track as she took different routes to get out of her third storey flat in Ang Mo Kio.
She would at times walk down the stairs, or go up to fifth storey common corridor and then take either of two lifts located there.
'We missed her on a couple of occasions because she took the lift at the end of the block rather than the one near her flat,' he said.
'Both she and Resham were suspicious. They would look around and changed their routes and modes of transport. At times they would travel by car and then get off and move on foot, and that made it challenging for us.'
For lawyer Tito Isaac, who represented the church and Father Simon, this project commissioned by his firm was also one of the longest surveillance projects he knows of.
'But Gilbert's team from SecureGuard came through with flying colours. All kudos to them for the work done,' he said.
'The evidence was there for all to see.'
Confirming identity of Madam Amutha, seen with sworn brother Resham Singh
29 to 31 Dec 2006
Catching her doing domestic chores and visiting the temple, looking personable
22 Jan 2006
Using public toilet in Yio Chu Kang gym, exercising with weights and on treadmill
31 Jan 2006
Seen walking alone from Bishan to Ang Mo Kio
Seen walking with stick and weak gait when at hospital but looking fit at other times, even walking across Causeway
This story was first published in The New Paper.