Sabrina and Yasmine Larbi-Cherif died in September last year.
A man who stabbed his girlfriend and her sister to death in their flat returned to the scene later to pay his respects, a court heard.
Mohammed Ali, of Old Snow Hill, Birmingham, has admitted the manslaughter of Yasmine and Sabrina Larbi-Cherif but denies their murder.
The 29-year-old was in a "on-off" relationship with Yasmine, 22.
He told Birmingham Crown Court that after stabbing them last September he returned to the flat and said a prayer.
Accused of rape
"I went up to the flat and I did pay my respects," he said.
He conceded he had a guilty conscience and added: "That moment I realised I made a big mistake in my life and I did ask for help."
Mr Ali has told the court that he attacked the sisters in their flat, in Jupiter Apartments in the city centre, because he was falsely accused of rape by Yasmine, a belly dancer.
He was charged with 12 offences but later cleared of the allegations after the prosecution offered no evidence.
Mr Ali said he "lost it" when Yasmine laughed at him about aspects of the five months he spent on remand in jail.
He said he then stabbed her 19-year-old sister after she hit him over the head as she returned to the flat after a walk.
However, prosecutor David Crigman QC said evidence showed Sabrina had blood on the soles of her feet, indicating she had walked in blood before she was attacked.
"The truth is that Sabrina was in the bedroom when all this began. You killed Yasmine in the lounge," he said.
"When you killed Yasmine, Sabrina was in the bedroom and she tried to come and save her sister."
Mr Ali said: "That's not true."
The trial continues.