Key evidence against a group of Indian activists accused of plotting to overthrow the government was planted on a laptop seized by police, a new forensics report concludes, deepening doubts about a case viewed as a test of the rule of law under Prime Minister Narendra Modi. An attacker used malware to infiltrate a laptop belonging to one of the activists, Rona Wilson, before his arrest and deposited at least 10 incriminating letters on the computer, according to a report from Arsenal Consulting, a Massachusetts-based digital forensics firm that examined an electronic copy of the laptop at the request of Mr Wilson's lawyers.