In the final day of testimony in the trial of Assemblyman Clarence Norman Jr., the lead prosecutor attacked the defendant’s argument that his failure to report campaign contributions was nothing more than an oversight.

In a cross-examination that lasted nearly four hours and was peppered with sarcasm, prosecutor Michael Vecchione suggested that Mr. Norman asked the defendant if his failure to inform his treasurer, Carmen Martinez, that a lobbyist was paying printing bills could be characterized as keeping her “out of the loop.”

“I make mistakes,” Mr. Norman responded, denying he had any intention of evading contribution limits. “No doubt about it.”

The prosecution chipped away at Mr. Norman’s credibility by pitting it against that of Ms. Martinez, whom Mr. Norman and other witnesses have repeatedly called trustworthy. An anchor of the defense’s argument is that the treasurer of Mr. Norman’s re-election committee, Ms. Martinez, made a mistake on a form. Ms. Martinez testified, however, that she filled out the form according to Mr. Norman’s instructions.

Mr. Vecchione asked Mr. Norman, whose testimony differed from Ms. Martinez’s, if she had lied under oath, eliciting one of numerous objections from the defense.

Once Mr. Norman had reaffirmed his belief in his treasurer, Mr. Vecchione yelled, “In fact, she had too much integrity for you to tell her. You didn’t tell her because you were afraid that once she knew, she would say ‘Clarence, we can’t take that because it is over the limit.'”

In a last effort to disparage the defendant, Mr. Vecchione questioned him while the jury was out of the courtroom about a packet of photocopies showing that he had laundered two political contributions into his own personal bank account years ago. Because it documented activities outside the scope of the case, the prosecution could only use the paper trail as evidence if it corroborated the witness’s testimony, but Mr. Norman, on the stand, claimed he had no recollection of making the transactions.

“The fact he doesn’t remember is ridiculous,” Mr. Vecchione said outside the courtroom. Although he was not allowed to show the photocopies of checks and deposit slips to the jury, Mr. Vecchione interrogated Mr. Norman with a litany of questions about the transactions he claimed not to remember, in order, Mr. Vecchione said, to portray Mr. Norman as “a thief.”

Mr. Norman, who has held an Assembly seat for 22 years and has led the Brooklyn Democrats for the last six years, allegedly solicited and failed to report more than $10,000 in contributions to his Assembly re-election campaigns in 2000 and 2002. He is charged with two counts of falsifying business records and two counts of violating election law by “knowingly and willfully” soliciting contributions in excess of the legal limit.

The initial list of 10 counts against Mr. Norman, which was shortened to six early in the trial, was cut again yesterday when the judge dismissed two counts on a technicality. Both of the remaining pairs of charges are felonies that carry a maximum prison sentence of four years.

After a two-day break, the trial will resume Monday with closing arguments.