Former deputy head teacher Sion Jenkins, charged with murdering his foster-daughter Billie-Jo, told a court on Friday how he found her blood-splattered body.
Jenkins told London's Old Bailey that his daughter Lottie screamed when she saw Billie-Jo lying in a pool of blood on the patio of the family home.
"The scene was horrendous," he said. "Her face was covered in blood. I couldn't cope. I knew I was struggling. I was scared."
The prosecution says Jenkins killed the 13-year-old with an 18-inch metal tent spike in February 1997. Jenkins, who denies the charge, is standing trial for a second time for the murder.
He told the court he had discovered the body after he arrived back home from a trip to a DIY store with Lottie and another daughter, Annie. He said he had left Billie-Jo alone at the family home in Hastings, East Sussex, to paint the patio doors so she could earn money to buy trainers.
Jenkins said at first he thought Billie-Jo had had an accident when he found her lying face down on the patio. He moved her shoulder so that he could see her face.
"Her back was towards me and I took her shoulder and pulled it over so I could see. Her face came up, and when it did it made a horrible chilling sound.
"Her face was bloody and her forehead was totally misshapen," Jenkins said. "Her eyes looked swollen."
Jenkins said he had not seen Billie-Jo in the three minutes they were back at the house but that Annie had spoken to her.
"The suggestion is that in that period you went out on the patio and murdered Billie-Jo. Is there any truth in that?" his defence barrister Christopher Sallon asked Jenkins.
"Absolutely no truth," Jenkins replied.
Jenkins was jailed for life in 1998 but the Court of Appeal quashed his conviction in 2004 as unsafe and ordered a retrial.
His defence lawyer said on Thursday that "grave doubts" remained over whether Jenkins committed the crime.
The trial continues.