Three people have been charged with the murder of 23-year-old university student Marco Tapia, who was shot at his family home in Glen Alpine, southwest Sydney, on 1 September. Police believe he was mistakenly targeted in an alleged gang assassination; his mother said the charges were welcome but each development renewed the family’s grief, and stressed that Marco was a caring biomedical engineering student with a future and a positive impact on others.

Police allege the two men, aged 22 and 23, and a 16-year-old collected a criminal contract and broke into the home armed with a handgun and crowbar. Investigators have not alleged which person fired the shot, and say they are still probing who organised the attack; the suspected intended target lived on the same street. Two other boys, aged 14 and 16, had earlier been charged over alleged preparation and clean-up roles. The three newly charged defendants remain in custody, with their cases due back in court in November.