Police arrested a man in his 40s on Thursday on suspicion of stabbing two junior high school students at a McDonald’s in the city of Kitakyushu, Fukuoka Prefecture, on Saturday, with one of the victims dying from her injuries.

Authorities said the suspect did not know the victims, and the seemingly random nature of the crime has led police to suspect that it was a “thrill killing,” according to a report by NTV.

Saaya Nakashima, 15, and a male classmate, also 15, were on their way home from cram school Saturday when they entered the McDonald’s at around 8 p.m. After securing a table, the pair joined the order line at the counter.