But his confession was met with understanding. His wife, Susan, and his children forgave him and welcomed Ava into their family in the months before the murder.

"People make mistakes," Susan Jackett told the CBS show 48 Hours. "He's only human."

When police questioned Jackett, he said he had nothing to do with Worthington's death and had no motive to hurt her. He acknowledged that she had again raised the issue of child support recently, but according to his lawyer, he saw "formalizing" their parenting agreement as a "positive thing." He gave police samples of his DNA to test against the semen and later said the results exonerated him . Investigators refuse to name suspects and have not confirmed the results of any lab tests.

Jackett tried to get custody of Ava after her mother's death, but ultimately a court placed her with friends of Worthington, as called for in her will.

Police also grilled Jackett's wife and his son and son-in-law, asking the younger men if they had conducted affairs with Worthington. According to Jackett, both denied it.

Friends pointed police toward another suspect, a heroin-addicted former prostitute who Worthington identified as her father's girlfriend. For months, Worthington had been complaining to friends that her 73-year-old father had lost his mind and was squandering her and Ava's inheritance on 29-year-old Elizabeth Porter.

Porter is HIV-positive with a criminal record. Her name also surfaced during a previous high-profile murder in Massachusetts. During the trial of Wellesley allergist Dirk Greineder, accused of killing his estranged wife, Porter was a key witness, testifying that he paid her for sex on two occasions. Greineder was convicted of first-degree murder and sentenced to life in prison.

According to Radlauer, Worthington told him "she had proof her father was paying rent for this woman and was paying for her car."

"She felt as though he was being reckless with the inheritance and she was talking about doing something about it," Radlauer said.

Immediately after Worthington's death, Porter, the daughter of a Boston cop, reportedly told people she was Christa's stepsister. Police questioned Porter and reportedly gave her and a live-in boyfriend polygraph tests. Since the murder, Porter was arrested for drug possession and hospitalized for an overdose. "Toppy" Worthington has said nothing publicly about his daughter or Porter.

Police also questioned the man who found Worthington's body, Tim Arnold. Arnold is a divorced father and children's book illustrator who lives with his father in a house behind Worthington's. She and Arnold dated after her relationship with Jackett ended and he even lived with her and Ava for four months. Ultimately though, Arnold told the Boston Globe, he and Worthington "drove each other crazy and didn't want anything to do with each other." Eventually, they rekindled a friendship and he enjoyed a close relationship with Ava.