Al was up with the sun. He told Yao he was going scouting and was not questioned. Approaching the cave mouth, he spotted Lok in the lookout tree, and waited for the right moment to slip past him unnoticed. He made his way quickly to where he'd found the broken branch. From there he picked up the trail.
It was harder than he'd expected. Whoever it was had known how to minimize the sign he left, and had done it as a matter of habit. He hadn't been actively trying to cover his tracks - there was no sign of that, and it would have made travelling too slow to be worthwhile. There was only one person in the group Al had seen move that way. But whoever it was may have been hiding their ability.
He followed the trail a lot further than he'd expected to. This guy was faster in the bush than he'd let on. It took Al two hours - so say one hour of walking for this guy, if he had vision enhancement, and they all did - to get to the end of the trail. And once he got there what he initially found nothing. But there had to be something, so he kept looking. It was getting hot. He sat down and tried to just feel the place, or feel what was out of place, but soon decided that was a load of hooey. If he wanted to do any finding, he'd better do some looking. Besides, the bugs bit more if he sat still, and he hadn't brought the old lady's hippie insect repellant. It was noon and he was nowhere. He checked his commlink, but there was no signal out here without Alyce's toys - he wasn't sure if she could reach the piece of junk he was carrying. But he wasn't giving up. He continued to meticulously search every possible space and surface in an slowly expanding circle. He felt like whoever had done this was laughing at him...what if they were? They knew he was a tracker. What if they took him into account personally when...he started looking well above his five-foot-three sightline - there it was, about seven feet up a Nepalese mango tree - there was a square unobtrusively cut into the bark. He reached up and peeled it off to find Chinese characters carved into the raw wood beneath. He recorded the image with his eyes, then collected some of the shavings. The Nepalese mango had a distinctive scent.
He couldn't read the symbols, nor access a translation program. But whatever it was, it had been intended for someone. So how would they have been expected to find it? Al knew what he'd have done, so he started climbing, choosing not the offending tree, but rather the tallest on in the vicinity, shimmying his way up into the branches, and then moving precariously up as high as he dared until the remaining limbs were too weak to support him. He looked out over the canopy and there it was, a bit of red paint at the top of the carved tree. He was pretty sure he knew what it was, and Alyce would know for sure. Not so high up that a climber couldn't have reached it. He climbed that tree and stripped off all the marked leaves, pocketing them. Then decimated the carving and replaced the bark.
He started backtracking. The guy had worked to retrace his steps, and done a good job. Al was looking for bootprints, but the guy wasn't that stupid. There was one muddy area around a small, almost stagnant creek where he'd had to make some, but here he had carefully rubbed them out. Tricky work in the dark, even enhanced, so Al poked around. There, at the water's edge. The water was lower now in the heat of midday - the print had been submerged slightly when the guy made it, and the lack of water flow had meant it was still there. More images recorded.
He had what he wanted, and made better time going back than he had going out. Yao looked a question, but Al just shrugged. "Nothin' movin', boss." Alyce was tending to Po and he waited. He smelled food and knew she'd have saved him some, so he just sat at his bedroll. It was between Xander's and Cheung's. Xander was over by Milo. Cheung was asleep after his night shift, boots on the floor. One lay on its side, the other was upright with a survival knife affixed.
When Alyce came over Al thanked her and started eating. He'd meant to be discreet at first, but having seen the boot, he no longer cared. He saw where Cheung's rifle leaned against the limestone wall, and knew he could reach it first. He opened up the wifi on his eyes, and spoke casually as he enjoyed her excellent cooking. "Check out today's recorded images." He watched her face as she realized the implications, and knew she was accessing Chinese translation databases. As she did so, he looked pointedly at the exposed sole of Cheung's boot. "What's it say?" Cheung didn't stir, but he imagined her fancy senses were picking up an increase in the Chinese scout's heart rate about now. She answered, "It gives the coordinates of the cave, and mentions the loss of Kang and Milo." Al pulled the red-dyed leaves from his pocket. "What's that?" She reached out and felt the sample, smelled it. "It's a marker with a radioactive isotope, readily visible in small amounts from high altitude drones. I'd have left it in a treetop." She smiled when his shrug confirmed that was where he'd found it. Al reached over and pulled Cheung's knife from its sheath. Cheung sat up. He looked at Al's grin and did not go for his rifle. Al sniffed at the knife.
"Nepalese mango, kemo sabe."