Government Laboratory senior chemist Dr Jimmy Tam told the court that curved, relatively widely spaced marks on Abby Choi’s bones were consistent with a circular electric saw. He was giving evidence for the prosecution in Choi’s murder trial.
Dr Tam said hand-saw marks tend to be straighter, closer together and parallel. But at a separate area near a bone joint, there were no distinctive tool marks, so he could not identify what caused it. He said it could have resulted from sawing or impact by a hard object such as a hammer; a large cleaver was also raised as a possibility.
School staff testified that on 21 February 2023, Choi’s daughter was still waiting to be collected at about 3.15pm. Calls to Choi, the child’s grandmother and her father did not get through at that stage. Asked who else might collect her, the child named her grandmother.
A school clerk said Choi’s former mother-in-law called at about 3.40pm from Kwun Tong, explaining that traffic had delayed her. She arrived at about 4.10pm, and staff checked her collection pass before releasing the child.