The teenager arrested after a 6-year-old boy was thrown from a viewing platform at the Tate Modern museum in London may have spent up to two hours Sunday picking out a victim, police said. The boy, who fell about 100 feet, is in critical condition; he's expected to survive. Police said they know of no motive, though witnesses said the 17-year-old shouted that it was social services' fault. The 6-year-old was with his mother when he was grabbed and thrown over the balcony; they were on a family visit from France. A detective said there's no connection between the suspect and the victim. "Every time I tried to move around with my children (the suspect) was there," one woman told the Mirror. "He was watching people. It was scary."
Bystanders later grabbed the suspect. Security guards evidently had thought the 17-year-old, who reportedly was standing calmly in a crowd of people who appeared to be in shock, was with the boy and took him into the cafe. When witnesses pointed him out, other bystanders held him, with one punching the suspect in the face. He was then locked in the bathroom until officers arrested him on suspicion of attempted murder. The museum, except for the viewing platform, reopened Monday. (An American tourist was killed by terrorism at another London landmark.)