A gunman opened fire inside an Illinois bowling alley, killing three people and injuring three others Saturday night in what authorities believe was a random attack.Police later said a 37-year-old man was taken into custody and no other people were being sought at the time after the attack at Don Carter Lanes.Rockford Police Chief Dan O’Shea said during a news conference that he did not think any officers fired their weapons.Two of those who were shot were teenagers, O'Shea said. The Rockford Register Star reported that 2020 has been the city's deadliest year for homicides, according to records that date back to 1965. Thirty-five people have been killed in the city this year, breaking the previous record of 31 in 1996.Rockford is about 80 miles northwest of Chicago.