Detective Testifies Wright Confessed to Raping Sister

April 14, 2011 Updated Apr 14, 2011 at 6:20 PM EDT

By John Borsa

April 14, 2011 Updated Apr 14, 2011 at 6:20 PM EDT

BUFFALO, NY (WKBW) - Luke Wright said he had sex with his "slow and handicapped" sister Laura Cummings at least 20 times before she was killed by their mother, a police detective testified on Thursday at Wright's rape and incest trial.

Erie County Sheriff's Det. John Graham told jurors that he interviewed Wright, 32, the day after his sister was killed and Wright confessed to having sex with his half-sister.

Wright is on trial for rape, incest, sodomy and assault before Erie County Court Judge Michael D'Amico.

Wright's attorney said his client did not understand that his statements would be used against him at trial.

"A retarded person characteristically does not begin to comprehend the situation which they find themselves," told reporters during a break in the case.

Det. Graham testified Wright made the statements after being notified of his right to remain silent and after Wright agreed to submit a sample of his own DNA.

"Luke would have signed anything they put in front of him," said Nuchereno, who is planning to use an insanity defense.

Wright has been found fit to stand trial by the court.

Reading from Wright's first statement to police, Graham told the jury that Wright admitted to covering Laura's head with a hood when she stared at him.

Graham read Wright's statement to the jury:

"I know that she's slow and handicapped. I used to tell her to stare down at the floor or I'd put that hood on her."

Prosecutors say Wright knew his actions were wrong. On the night of January 21, 2010, the day Laura was killed, Wright returned home from work and found police outside the Sherman Avenue apartment he shared with the family.

Instead of going inside, Wright ran to a neighbor's house.

"In his own words, he tells us, 'I didn't come home when I saw all the police cars at my house because I didn't want to be questioned about what had been going on in the household. I was afraid since I was involved with tying up Laura and with the sex and all, that I would be hung for this,' " prosecutor Kristen St. Mary told jurors during opening statements on Tuesday.