There's been yet another mass shooting in the United States – this time at a medical facility in Tulsa, Oklahoma. Police say four people were killed, and the shooter died of a self-inflicted gunshot wound. It marks the 20th mass shooting since the elementary school massacre in Uvalde, Texas. Reagan Ledbetter of CBS affiliate KOTV in Tulsa reports the latest. Each weekday morning, "CBS Mornings” co-hosts Gayle King, Tony Dokoupil and Nate Burleson bring you the latest breaking news, smart conversation and in-depth feature reporting. "CBS Mornings" airs weekdays at 7 a.m. on CBS and stream it at 8 a.m. ET on the CBS News app. Subscribe to “CBS Mornings” on YouTube: https://www.youtube.com/CBSMornings Watch CBS News: http://cbsn.ws/1PlLpZ7c Download the CBS News app: http://cbsn.ws/1Xb1WC8 Follow "CBS Mornings" on Instagram: https://bit.ly/3A13OqA Like "CBS Mornings" on Facebook: https://bit.ly/3tpOx00 Follow "CBS Mornings" on Twitter: https://bit.ly/38QQp8B Subscribe to our newsletter: http://cbsn.ws/1RqHw7T​ Try Paramount+ free: https://bit.ly/2OiW1kZ For video licensing inquiries, contact: [email protected]