Fla. Shooter May Have Donated Blood to His Own Victims Omar Mateen had donated blood 2 weeks prior to shooting By Evann Gastaldo, Newser Staff Posted Jun 15, 2016 2:52 PM CDT 35 comments Comments This undated file image shows Omar Mateen, who authorities say killed dozens of people inside the Pulse nightclub in Orlando, Fla., on Sunday, June 12, 2016. (MySpace via AP, File) (Newser) – On May 29, Omar Mateen donated blood at a OneBlood mobile blood drive. Two weeks later, he opened fire at Orlando's Pulse nightclub, killing dozens and injuring dozens more—and OneBlood provided much of the blood supply used to help the victims, ABC News reports. The donation center confirmed Mateen's donation Wednesday: "OneBlood has learned that Omar Mateen donated blood at a mobile blood drive in Ft. Pierce, Florida, on May 29," says a statement. "All facets of the donation were in our normal parameters for blood donation, including screening questions and post-donation blood testing." OneBlood did not specify whether Mateen's blood has been used.