Chelmsford Crown Court has been hearing from Detective Sergeant Michael Ruddockwho took a statement from Edward Redman's girlfriend at the time Shannon Fenlon. She'd known him two years and they'd been going out for 15 months.
Edward Redman is accused of murdering Jay Whiston, 17, a house party in Colchester in September 2012.
In her statement Shannon Fenlon said how she was with friends at another party on 8 September 2012. She'd messaged Edward during the night saying: "Are you ok" he replied "Yeah."
He came back to hers after the party. He seemed quiet and looked tired.
In the morning she noticed a scratch on his back. He said there had been a massive fight at the party.
He didn't say he was involved but she assumed he must have been.At 12.30pm she turned on her Blackberry and saw loads of status updates about Jay and people posting their sympathy but she didn't know who he was and didn't connect it to the party Edward was at.
At 8pm that night Edward's brother rang to say Edward had been arrested and police were searching their home. DS Ruddock said texts had been deleted from her phone.
Edward Redman, 18, denies murder and the case continues.