Small strands of evidence built the case against killers
Three dog walkers who were enjoying the amenities in St Catherine's Park in Dublin on the evening Ana Kriegel disappeared gave evidence during the first week of the trial.
It would be easy to gloss over these witnesses - indeed none of them spent very long in the witness box nor were they cross-examined to any great lengths - and think their evidence was inconsequential.
However, their accounts, taken together with nearly 700 hours of CCTV footage, were part of the meticulous building of the case against the two defendants by gardaí.
First to take the witness stand was a girl out walking her dog.
She knew both Ana and Boy B and saw them walking diagonally across the football field.
They were "laughing and talking" and "they seemed to be having a good time", she said.
The teenager said she was too far away from Ana and Boy B to talk to them and did not think they noticed her.
This account fitted with CCTV footage, which although hazy, showed two people walking across the football field at the specified time.
A second witness gave evidence he was out walking his dog in the park when he saw Boy A.
He estimated the time as just after 5.44pm.
He was near the small car park when he spotted a young lad who appeared to be "walking with a funny gait".
When the boy got closer he realised it was Boy A, who he knew.
He said Boy A "looked like he'd been hit", and there appeared to be something that could be blood on his T-shirt.
He said Boy A told him he fell and "hit himself".
Boy A also seemed "embarrassed" and the witness felt he may have been bullied and just wanted to go home.
Although there was no CCTV footage of this meeting between the man and Boy A, the dog walker's account and the time fit with other CCTV coverage which gardaí collected.
A second dog walker, Gerard Redmond, said he saw a schoolboy make a beeline for the disused building where Ana's body was later found on the evening she was last seen.
Mr Redmond said it was 5.07pm or 5.08pm when he saw a schoolboy in front of him.
He was wearing a backpack and was walking along the top of a low embankment.
Mr Redmond said the boy suddenly "dropped down into the ditch and came up the far side into a large field that surrounds a disused farmhouse".
Gardaí believed this person was Boy A.
It also fitted with CCTV footage of a boy identified as Boy A by his co-accused in an area of the park known as Meadowfields around the same time.
This was "really strange", Boy B later said in interviews, before telling gardaí about a shortcut which Boy A could have taken back to where he [Boy B] had said he and Ana had met Boy A.
Meanwhile, Boy A's father said his son was shaking and very rattled on the evening Ana went missing and told him he had been attacked by two men.
His father wanted to report it to make sure it didn't happen again and he and his son went for a drive to see if they could locate the two offenders.
He said they went to the park and Boy A pointed out the rough area where the "two lads hopped on him".
Boy A subsequently showed Detective Garda Gabriel Newton where he said he'd been assaulted.
His father asked the park ranger if he had seen anything and he hadn't.
In his evidence, Park Ranger Norman Macken said he noticed small bits of blood on the fingers, face and trousers of a teenager who told him he "got a bit of a hiding" in the woods.
Mr Macken said he spoke to the boy after his father knocked on the ranger station to complain his son had been "jumped" in the woods by a "couple of big fellas".
Mr Macken said he asked the boy what had happened.
The boy put his hand to his eyes and told him that he "just got a bit of a hiding in the woods".
The boy's hands were shaking and Mr Macken said he did not seem to want to engage with him.
The day after Ana disappeared, gardaí and Boy B retraced the route which he said he'd taken with Ana.
Boy B showed Sergeant John Dunne where he claimed he had last seen Ana.
He said Ana went one way, and he and Boy A walked off in separate directions.
That afternoon, Boy A and Boy B walked the route a second time with gardaí.
At one point, the boys took a right turn on a wooded trail and Sgt Dunne asked Boy B if this was correct as he had previously gone left.
"Boy B stopped and he stated he went no further than this," Sgt Dunne said.
"I observed Boy A having a glance, a look at him."
Nothing was said, he added, and Boy A denied it.
However, this look was enough to raise gardaí suspicions and they became concerned about inconsistencies in the boys' accounts.
The discrepancies were confirmed as they gathered the CCTV footage.
Gardaí later gave evidence of the time it would have taken to walk the 3km from Ana's house to Glenwood House.
Depending on their walking speed it ranged from 19 to 24 minutes.
These small pieces of evidence and the CCTV footage helped gardaí to prove three things.
It helped to prove that Boy B was lying during interviews with gardaí - as the route Boy B claimed they took did not match what was captured by the cameras located at St Catherine's Park.
Secondly, there was no CCTV footage or visual sightings of three people together in the park, casting doubt on Boy B's claim he and Ana had met up with Boy A in the park.
Thirdly, the CCTV footage cast doubt on Boy A's assertion he had been attacked in the park, as the alleged culprits, who he described in detail to gardaí, were not captured on any cameras.
Ultimately, these small strands of evidence also helped to convict Boy A and Boy B of Ana's murder.