The 12, who had all faced charges in Hong Kong linked to anti-government protests, have been held virtually incommunicado in a mainland prison since they were detained at sea, apparently while trying to reach the democratic island of Taiwan. A relative of one of the detainees told Reuters on Friday she doubted the fairness of the legal process for the 12. They face charges of illegal border crossing and organising an illicit border crossing, which could carry a sentence of up to seven years in jail, mainland authorities said. “The investigation of 12 Hong Kong people who were found unlawfully crossing the border has ended,” authorities in Yantian district of the southern mainland city of Shenzhen said. The 11 men and one woman were captured by the Chinese coastguard on Aug. 23. The youngest is 16. In a joint statement, families of seven of the detainees said this month their lawyers, chosen from a list provided by Chinese authorities, passed on letters similar in content, all describing good conditions in prison and urging their families and neighbors back home not to worry. The families said they were suspicious of the praise in the letters describing how well they had been treated in prison. Beatrice Li, sister of Andy Li, one of the detained, told Reuters on Friday: “It is not a fair legal process that they are undergoing.” The father of detainee Cheng Tsz-ho said: “The faster the trial, the faster we can know how long they will be detained ... I hope we can ... have a fair and just judicial trial.” Their case has attracted a lot of interest in the former British colony as a rare instance of Chinese authorities arresting people trying to leave at a time of growing fears about prospects for the city’s high degree of autonomy. All of the 12 had faced charges in Hong Kong linked to an anti-government protest movement, including rioting and violation of a contentious national security law that China imposed in June. Authorities have denied family and lawyers access to the 12, insisting they be represented by officially appointed lawyers. Reporting By Sharon Tam, Twinnie Siu and Jessie Pang; Writing by Anne Marie Roantree, Editing by Robert Birsel and Timothy Heritage