A triple killer is set to become the first man executed with a working defibrillator in his chest when he is put to death in Tennessee today. Byron Black's bid to delay the execution was denied on Monday, and he will now be killed by lethal injection. There is uncertainty over whether the device will shock his heart, potentially prolonging his death and causing suffering when the deadly cocktail takes effect. Black shot dead his girlfriend Angela Clay and her two daughters, aged six and nine, in a jealous rage in 1988. He committed the murders while on work release for shooting Clay's estranged husband. Read more on the story on the Sky News website: https://news.sky.com/story/byron-black-to-be-first-man-executed-with-working-defibrillator-fitted-despite-claims-he-could-suffer-13407237 #USNews #ByronBlack #UnitedStates SUBSCRIBE to our YouTube channel for more videos: http://www.youtube.com/skynews Follow us on Twitter: https://twitter.com/skynews Like us on Facebook: https://www.facebook.com/skynews Follow us on Instagram: https://www.instagram.com/skynews Follow us on TikTok: https://www.tiktok.com/@skynews For more content go to http://news.sky.com and download our apps: Apple https://itunes.apple.com/gb/app/sky-news/id316391924?mt=8 Android https://play.google.com/store/apps/details?id=com.bskyb.skynews.android&hl=en_GB Sky News Daily podcast is available for free here: https://podfollow.com/skynewsdaily/ To enquire about licensing Sky News content, you can find more information here: https://news.sky.com/info/library-sales