Attorneys for the man accused of a series of rapes along the East Coast have notified Prince William County prosecutors that they intend to argue at trial that Aaron Thomas was insane when he allegedly abducted three teenage trick-or-treaters and raped two of them in Woodbridge in 2009.

Thomas, 41, has been linked by DNA to at least 12 rapes in Virginia, Maryland and Connecticut dating to the 1990s, and police say they think there were more. Thomas — whom police have called the East Coast Rapist — was captured in March 2011 after a long manhunt led them to New Haven, Conn., where they surreptitiously gathered his DNA. The Halloween 2009 case re-energized the investigation, drew extensive media coverage and ultimately elicited an anonymous tip about Thomas.

Ronald Fahy, one of Thomas’s attorneys, said in court papers filed in Prince William Circuit Court that he plans to argue that Thomas was legally insane at the time of the offense and “may present evidence of an expert to support his claim.” Such a strategy would imply that Thomas would concede he was involved in the rapes but did not understand the consequences of his acts, did not know right from wrong at the time or had an irresistible impulse to commit the crime.

Police have said they collected Thomas’s DNA at the scene, and Thomas has acknowledged to police that he raped the girls, according to testimony at a preliminary hearing in the case. Police have said Thomas would have “urges” prior to such attacks.

Insanity defenses in Virginia, which are rare, require defense attorneys to meet a fairly high burden of proof to establish their client was insane at the time of the crime. And insanity at the time of the offense differs from one’s mental competence at the time of trial. Thomas’s attorneys also have asked the court to allow for a mental competence evaluation, arguing that he has not cooperated with his defense and “lacks substantial capacity to understand the proceedings against him or to assist his attorneys in his own defense.”

Jennifer Zary, who also represents Thomas, wrote in court papers that Thomas has mutilated himself while in jail, has refused to meet with his defense attorneys and hid under a blanket when she tried to speak with him through his cell door in the Prince William jail.

“Without contact, Defense Counsel has been unable to advise Aaron Thomas that his refusal to meet with the mental health evaluator could preclude him from presenting a sanity defense at trial,” Zary wrote. “Defense Counsel has been unable to discuss the elements of these charges with Mr. Thomas, advise him of his Constitutional rights, or discuss any aspect of the trial currently docketed for July 31, 2012.”

A hearing is scheduled for Friday to determine whether Thomas can have such a mental competence evaluation. According to court records, the court ordered an evaluation of Thomas’s sanity at the time of the offense, and Thomas refused to meet with that evaluator.

Responding to the defense filing, Commonwealth’s Attorney Paul B. Ebert, who received the case from Connecticut prosecutors, wrote that Thomas has already been evaluated to determine whether he is competent to stand trial. The doctor found Thomas to be malingering during her interviews and said he was “feigning” or “greatly exaggerating” mental symptoms “in order to avoid prosecution by being deemed incompetent,” Ebert said.

The prosecutor wrote that if defense attorneys plan to present evidence of insanity, prosecutors are entitled to a separate evaluation of Thomas. Under Virginia law, if a defendant refuses to cooperate with the prosecution’s evaluation, other evidence of insanity can be barred from trial.

Thomas faces a maximum of life in prison if convicted on charges of abduction, rape and use of a firearm in the Woodbridge attack. He could face additional trials in Virginia, Maryland and Connecticut, where he allegedly attacked women near places he lived or to which he traveled.