Like a prize fighter who gets his second wind after surviving a standing eight-count, Margaret Rudin's lead defense lawyer came back swinging Monday in his cross-examination of a prosecution witness who inflicted a lot of pain last week on her own sister.

  Michael Amador, who learned formally Monday morning that his pro bono client will not get a mistrial, took on Margaret Rudin's sister with first-round vigor. It was Dona Cantrell-Robinson's testimony last week — that Rudin did not seem concerned about the 1994 disappearance of her unfaithful husband, Ronald Rudin — that prompted Rudin to unsuccessfully seek a mistrial on the grounds that Amador was not prepared for Cantrell and other witnesses.

  Amador perhaps redeemed himself when the trial got under way Monday afternoon. Taking the stand again, the 49-year-old Cantrell was asked by Amador about her rocky relationship with her sister Margaret, her assistance to the prosecution, and $2,000 she was paid for an interview on the tabloid television program "Hard Copy."   "You were never close with Margaret were you?" Amador asked, barely allowing Cantrell time to respond before firing his next question.

  "Throughout your lifetime, since you were teenagers, you were never close to sister Margaret, were you?" Amador, raising his voice for the first time since testimony began March 2, asked Cantrell.

  "You were enemies, weren't you," he pressed later.

  Cantrell conceded that her relationship with Rudin, 57, was on again, off again — mostly off over the years. She insisted that she was close to her sister at times and that Rudin was confiding in her around the time that her fifth husband, 64-year-old millionaire real estate mogul Ronald Rudin, disappeared in December 1994. His charred remains, revealing four bullet-holes in the skull, were discovered a month later. His wife faces a possible life sentence if convicted of his murder.

  Amador tried during more than four hours of cross-examination to show that Cantrell hated Rudin, was happy to assist the prosecution and even profited from it.

  Cantrell has not always been forthcoming with information, Amador established during questioning. In December 1995, the first time she was ever under oath, Cantrell invoked her Fifth Amendment right against self-incrimination and refused to answer Rudin's questions during a deposition in a civil trial over Ron Rudin's $11.3-million estate.

  Wearing a powder-blue blouse, Cantrell shifted in her seat as Amador's voice grew louder. He pressed her about what police had told her about their investigation and when, as well as her refusal to give any information that might be helpful to her sister.

  "Her bias is established by [the fact that] the only opportunity she has to establish the facts and the truth in this case, and she took the Fifth," Amador told Judge Joseph Bonaventure. The judge permitted Amador to ask five questions to establish that Cantrell invoked her constitutional right in refusing to answer Rudin's questions in 1995.

  "I think I said that 167 times to both sides," Cantrell said.

  Outside the presence of the jury, Amador successfully argued that the line of questioning was relevant because it showed that Cantrell was out to get her sister.

  "This is the first opportunity she had to help or hurt her sister," Amador said. "It establishes her own bias against her sister."

  Co-defense counsel Tom Pitaro likened Cantrell's acceptance of $2,000 from "Hard Copy" to the betrayal of Jesus Christ to the Romans by Judas Iscariot for 30 pieces of silver, leading to his crucifixion.

  "Apparently $2,000 is the inflation rate of 40 pieces of silver after 2,000 years," Pitaro said at one point.

  Bonaventure was a bit softer during his admonishments of Amador Monday afternoon, the first time a witness testified since Rudin requested a mistrial Thursday. Among other things, Rudin had complained unsuccessfully that she was not getting a fair trial because Bonaventure was reprimanding her lawyer in front of the jury.

  Bonaventure took Amador to task for asking Cantrell if she told her husband last year that she had an intimate relationship with a homicide detective on the case. The judge previously ruled that the statement — which Cantrell denied making — was not a proper subject for cross-examination.

  Amador's cross of Cantrell resumes at 12:15 p.m. ET on Tuesday.