Rahul Chandra was a man who lost his sister, Asha Chandra, in mysterious circumstances. He sought to find out what had happened to her.
He filed a police appeal for assistance, but in the coming years, turned instead to alien conspiracy theories, and monitoring energy readings in Sheffield in order to build predictive programs. After seven years of keeping up with this research, since her disappearance, and gathering files, he eventually found the pod again that emitted the creature which stole his sister.
After paying Andy to help deliver the pod with his lorry to Rahul’s warehouse, he spent the night waiting for it to open, setting up cameras to monitor the object. While waiting, he made a video explaining why he took the pod and left it on his computer desktop for others to find, should he ever die in his quest.
When the pod finally opened, he confronted the creature inside, Tzim-Sha, demanding to know what he did with his sister. The alien advanced on him, stating he would never know before freezing him to death.
The Thirteenth Doctor later found his corpse, with Grace, Graham, Ryan and Yas. They discovered that Tzim-Sha had stolen a tooth from Rahul as a trophy, and later uncovered the video he had left behind. (The Woman Who Fell to Earth)