Shocked sports stars turned to Twitter after hearing that Oscar Pistorius had allegedly shot and killed his girlfriend.
Olympic stars told of their surprise after Pistorius was arrested after a body was discovered at his home in South Africa.
Many were reacting to reports that Reeva Steenkamp, 30, had been killed by accident as she surprised the track star for Valentine's Day, before he was charged with murder.
Heptathlon champion Jessica Ennis wrote: "Woken up to the horrendous news about Oscar Pistorius mistakenly shooting his girlfriend. What an awful tragedy."
Retired heptathlete Denise Lewis said: "Not a good morning athletics fans - News reports on Oscar Pistorius are unbelievable!!!"
Double Paralympic gold medallist Hannah Cockroft supported the track and field star, posting: "Everyone makes mistakes. My thoughts are with everyone involved, you're still a hero to me."
Paralympic cyclist Jody Cundy added: "Thoughts out to the families of @reevasteenkamp and @OscarPistorius sad and tragic news."
And football star Michael Owen wrote: "My word, if these reports on Sky News are true, this story regarding Oscar Pistorius accidentally killing his girlfriend is horrific."
Meanwhile author Tony Parsons said: "The tragedy of Oscar Pistorius is he somehow climbed to the top of the world but did not feel safe enough to sleep without guns by his side.
"In a summer of heroes nobody came even close to Oscar Pistorius - not even close - and this is such a tragedy for him, the girl and all of us."