A suspected lone gunman killed at least four people and wounded three others, including a police officer, in a string of shootings across the Denver metropolitan area of the <a href="https://www.thenationalnews.com/tags/us/" target="_blank">US</a> state of Colorado on Monday. The “very violent series of events” took place across four locations and ended with police killing the gunman, authorities said. Police said they were still investigating what led to the shootings. “We need to dig in and find out what the motive was behind this,” Denver Police Chief Paul Pazen said at a news conference. “To have this type of spree take place is not normal for our community.” The shootings began at about 5pm local time when the gunman, who has not been publicly identified, shot and killed two women and wounded a man near the Denver city centre, said Mr Pazen. The gunman then fled in a car and fatally shot a man in east Denver's Cheesman Park neighbourhood before opening fire again in a west Denver community where no one was hit, Mr Pazen said. He referred to the events as a “killing spree”, <i>The Denver Post</i> reported. He said the gunman twice exchanged gunfire from his vehicle with Denver officers pursuing him, disabling a police car. From there, the gunman drove into the neighbouring city of Lakewood, where he shot and killed a fourth person inside an unspecified business, Lakewood Police spokesman John Romero said. The gunman fled from Lakewood police when they attempted to pull him over and engaged in a running gun battle with officers before fleeing on foot and entering a hotel, where he shot and wounded a clerk, Mr Romero said. He then shot at officers again, wounding one of them, before police shot him dead, Mr Romero said, and added that the officer was undergoing surgery. “It's a tough day for the Lakewood police family,” Mr Romero said. “We just ask everyone in our community for their thoughts and prayers for that agent and for their family.” <i>The Associated Press contributed to this report</i>