Raleigh, N.C. — Michelle Young's father told investigators his son-in-law is methodical, very smart and can change who he wants to be, according to new search warrants in the unsolved murder case of the 29-year-old pregnant mother.

"We're convinced he's a chameleon," Alan Fisher told Wake County sheriff's investigators. "He is what you want him to be, and he's got multiple personalities and he leads you to believe that that's the person he is. The minute he's out of your presence, he's a chameleon to someone else."

Jason Young's attorney, Roger Smith, had no comment Tuesday about the statement or about the latest warrants.

Michelle Young was found beaten to death inside her Wake County home on Nov. 3, 2006. Her daughter, Cassidy, then 2, was found unharmed in the same room, authorities have said.

Investigators have made no arrests in the case, but Jason Young, who has been a focus of their work, is referred to as a primary suspect in Tuesday's warrants. He told authorities he was out of town on business when his wife was killed.

The warrants also reveal that DNA on a medicine dropper containing liquid residue and found in Cassidy's bedroom matched hers.

Investigators believe that whoever killed Michelle Young might have tried to drug the girl to keep her from interfering, according to a July 25, 2007, warrant.

The latest warrants, issued Feb. 9, were for two Hotmail e-mail accounts belonging to Jason Young. Investigators say he used them in a Dec. 13, 2006, e-mail exchange with Fisher.

In those e-mails, Fisher, who died last summer of cancer, writes that he wants to be supportive of Jason Young but that Young has not been up front in answers about an extramarital affair.

"I feel very put off and I am not happy," Fisher writes. "We will not under any circumstances turn our backs on you, but I need to know that you are being forthright with me."

In an interview with Detective Richard Spivey, Fisher also said that Jason Young's actions during a visit led him to become "much more suspicious" of Young.

Fisher said that Jason Young never tried to tell him that he was not involved in his wife's death and that he seemed to be on "top of the world. It was like Michelle was a thing of the past."

The affidavit that supported investigators' request for the search warrant states the visit was in March, but it's unclear how long after the slaying.

Last month, a judge ruled in a wrongful death lawsuit filed by Michelle Young's mother, Linda Fisher, that Jason Young was responsible for Michelle Young's death. Young missed a deadline to respond to that lawsuit, so the judge ruled for Fisher by default.

Legal experts say the ruling has nothing to do with guilt or innocence, but it means Young won't be able to collect benefits from his wife's life insurance policy.

Last week, Young and Linda Fisher reached a settlement in a custody dispute over Cassidy. He and Michelle Young's sister, Meredith Fisher, will share custody.