MADISON, Wis. (AP) – Police in Milwaukee are warning pedestrians to watch out for so-called knockout attacks. The Milwaukee Journal Sentinel and WTMJ-TV reported Wednesday a 53-year-old man was serious injured in what could have been a knockout attack. The man, Tim Bessette, told WTMJ that a group of teens started harassing him as he was walking Monday evening. One of the group punched him, breaking his nose and fracturing bones in his face. Three other attacks punched him several more times. Knockout attacks involve groups of youth who randomly target pedestrians with the intent of knocking them out with one punch. The assaults have gained national attention after high-profile attacks in several cities.