The man argued that evening's vandalism was part of a concerted campaign to drive the remaining residents out, and that the developers who had already bought up three of the flats were behind it. Eventually, one of the officers shot a weary look at his colleague and slowly got out his notebook.
Inside his shop, a sombre Mr Wong handed Grandad a tin of paint he'd just retrieved from a cupboard.
"Thanks," said Grandad. He paused. "Sui-man knows nothing about what's been going on here and I want to keep it that way."
As Wong nodded, the young man entered, angry and frustrated. "The police say I'm making a very serious allegation without any proof."
"Do they think intimidating the old people that live here isn't very serious?" Wong demanded bitterly.
"And never mind proof, they should just ask themselves who's going to benefit if the owners are scared into selling," said Grandad.
"Did you tell them about the phone calls everyone has been getting?" Wong continued. "And how those sharks have left the windows open in the flats they've bought, so the rain can damage the structure of the building?"
"Yes, yes, yes. They say they'll investigate, but ..." The young man shook his head sadly. "I don't want to advise my grandmother to sell, but if this carries on, what can I do?"
Grandad and Wong looked at each other in dismay.
"Yes, she is," Ethan told his sister Sophie during their video call the next day. "She's much, much better."
He wasn't lying, as he hadn't lied to her in all their other calls since Mum's relapse. However, he was putting a very optimistic spin on things. Ethan knew if he told Sophie the unvarnished truth and she quit medical school in Australia to return home, Mum would freak out and her condition could nose dive.
"And how's gung gung?" Sophie asked.
"He's ... fine." Now this was, in Ethan's mind at least, a 100 per cent, outright fabrication.
Last night Grandad hadn't turned up at the computer store to meet Sam, Jenny and Ethan as arranged. Although he claimed he'd just dozed off at his shop, when he'd eventually returned home his hands were covered in paint and he had no explanation of how it had got there.
Ethan suspected Grandad was beginning to lose it.
Yet Grandad wasn't the only person close to losing it. As a couple of his gang lounged on the children's climbing frame in the Ki Lung Public Housing Estate, Tam Wai-hung sat brooding beside them.
In his warped view of what constituted justice, when Ethan turned down his offer of "work", he had not only caused Wai-hung to lose face, he had also cost him money. While beating up Ethan might temporarily ease his irritation, he wanted his revenge in cold hard cash.
And his mood wasn't improved by the return of a sullen-looking Leung Yiu-hon with the news he'd been unable to sell any of the drugs he had been given.
Wai-hung shoved Yiu-hon - recently released from a young offenders institute - in the shoulder. "What's the matter with you? Do I have to teach you everything?"
Grandad stood in the alley behind his shop, looking at the wall he'd painted the previous night. Although the threatening graffiti the vandals had scrawled across it was now invisible to the eye, its message was burnt into his mind.
For 45 years he'd worked here, taking over the management of the business when his boss had retired. The flats above it that remained occupied, as well the shop next door, were full of his oldest and dearest friends. This place, together with his family, were his life.
Ethan had tried to convince himself that Grandad was just getting a little tired. But when he arrived to find him staring at the repainted brickwork, and realised this was what he had been doing the previous evening, Ethan's faith in this explanation began to crumble.
However, there was no hint of this fear in his warm greeting, or his gentle reminder that they needed to buy external drives to back up their work on shamefacebook.
"You were right not to let Sam pay," his grandad told him. "We'll go together tomorrow. I promise."
It took a moment for Ethan to summon up his courage before asking: "Gung gung, do you think running the shop might be getting a little too much for you?"
Even though he knew he was walking on eggshells, Ethan was unprepared for the explosion of rage this triggered. "So, you want me out of here as well!"
Ethan looked down at the list his grandfather had given him, put his rucksack in the trolley and eased his way down the crowded supermarket aisle to get to the rice.
He was still worried about Grandad. Mrs Wu, their neighbour, had warned Ethan that a man of his age shouldn't be putting himself under such strain. And it was clear to Ethan something was seriously wrong. But when he'd tried to talk to Grandad earlier he'd been met with just an angrily defensive response.
It was at times like these that Ethan began to feel overwhelmed by the burdens he seemed to have to carry all on his own.
He couldn't share the load with his sister in case she jumped on the first plane back from Australia. And his only surviving parent was lying in a hospital bed.
Yes, there was Sam - but he was just a teenage boy like himself, always ready with a well intentioned but simplistic solution. And Maya ... well he'd clearly blown his chances with her through this destructive need for secrecy.
As he headed back down the aisle, lugging the bag of rice, Ethan realised he couldn't see his trolley. With a mounting sense of urgency he began to push his way through the shoppers. Suddenly he saw it, his bag still sticking out, just not where he thought he'd left it.
Man, he needed to pull himself together before he sank without trace into a swamp of self pity.
At home, after he'd put away the shopping, Ethan unzipped his rucksack to get out his laptop. But it wasn't there.
His mind began to race. Had he left it at Sam's? No, he clearly remembered packing it away before he left. Could it have fallen out? Maybe at the supermarket? Before he started to really panic he should go back and check.
He was about to head out the door when a thought suddenly struck him. In order for his laptop to have fallen out, his bag would have had to have been open. But just now he'd unzipped it ... The only possible explanation he could see was a thief had removed his computer before zipping up the bag again.
Standing alone in the kitchen, Ethan's blood began to run cold as the realisation dawned on him that, while the laptop was just about replaceable, no other copy of all the coding and design work they had done on his website existed.
To be continued next week