Switzerland has instituted criminal proceedings following a July 29 attack on foreign cyclists in Tajikistan, in which a Swiss man and three others were killed, Swissinfo reported on August 2.

The attack, claimed by the Islamic State (IS) terror group, injured three other people, including a Swiss woman who flew back to Switzerland on August 1.

The Office of the Attorney General announced on August 2 that it had opened a criminal case against persons unknown on suspicion of murder, severe personal injury, membership or support of a criminal organization, and violation of the law banning al-Qaeda and the Islamic State and related groups.

According to the office, this is the usual procedure for alleged attacks affecting Swiss citizens.

The Swiss Foreign Affairs Ministry has since updated its travel advice for Tajikistan, including several lines about how the cyclists were hit by a car in the Danghara district before being attacked with knives, according to Swissinfo.