LONDON (AP) — British police have arrested a fifth man in a suspected acid attack on a three-year-old boy.

West Mercia Police said Tuesday that a 41-year-old has been detained over alleged conspiracy to commit grievous bodily harm.

The young boy was attacked at a shopping center in Worcester in western England and treated overnight in a hospital for severe burns to his arm and face. Officials say the long-term health implications of his injuries are not yet clear.

Police say the boy was deliberately targeted. There has been no explanation of a possible motive.

The five suspects have not been named or charged.

Police have reported an increase in acid attacks in Britain in the last year.