Michael V. Townley is "a man you don't have to like and probably don't, but he's a man who told the truth."

Or he is "a bald-faced liar... a man who talks about eliminating people as if they were bugs."

These two dramatically different views of the government's chief witness were presented yesterday by prosecutor E. Lawrence Barcella, Jr. and defense attorney Paul Goldberger as they made their final arguments in the Orlando Letelier bombing assassination trial.

With the jury listening raptly, Barcella, Goldberger and fellow defense lawyers Lawrence Dubin and Oscar Suarez disparaged each other's cases for and against the three anti-Castro Cuban defendants charged in connection with the 1976 murder. Yesterday's arguments, like much of the five-week trial, homed in on the credibility of Townley, the Americanborn Chilean secret police agent who has confessed to planting the bomb that killed former ambassador Letelier.

Barcella, pointing to charts and displaying government exhibits, told the jury that defendant Alvin Ross Diaz had called Townley "a rat, a traitor, and an informer, but never a liar."

The prosecutor paced back and forth in front of the jurors for two hours, but stood still in front of a lectern when he pointedly said, "Only an insider can unravel the conspiracy. Only an insider can breach the secrecy (surrounding the slaying). You need an insider. With Michael Townley you found out what was happening in Chile and the U.S."

Barcella said that the 36-year-old Townley was "so concerned about telling the truth" that at one point in his six days of testimony, when he felt he had misstated a fact, he immediately turned and apologized to Judge Barrington Parker.

To varying degrees, Townley implicated all three Cubans in the Letelier slaying, a mission Townley said came directly on orders of his superiors in the Chilean secret police, formerly known as DINA. Ronni K. Moffitt, a colleague of Letelier's at the Institute for Policy Studies, was also killed in the bombing at Sheridan Circle.

As Barcella recited the intricate details of the assassination plot, he regularly told the jury at key junctures, "Orlando Letelier comes a little closer to dying."

The prosecutor discounted defense's efforts to show that Townley had actually killed Letelier on orders from the Central Intelligence Agency. "What did the defense produce to substantiate the grand promises (in opening arguments)?" Barcella asked.

"I submit essentially nothing. You can't be swayed by fantasy. You can't be swayed by something that isn't there," he said.

But Goldberger compared the government's case to a building that is "built on a foundation of mush and garbage. You can't put anything else on top of it."

The government's case, he said, relies almost totally on Townley, whom he described as "a man who would kill without regret, without conscience.

"Is he psychotic?" Goldberger asked rhetorically. "Is he crazy?" Maybe. Is he stupid? No. He's an absolute perversion of our system of justice.

"There's something Mr. Townley has less familiarity with than most of us -- the truth," Goldberger told the jurors.

The defense attorney claimed that Townley had admitted in his testimony that he had lied 42 times in a 14-page statement to a Chilean general. The general had been assigned to determine the extent of the Chilean government's involvement in the Letelier killing before Townley was turned over to the FBI to testify in the current case.

Goldberger and Dubin conceded to the jury that they may not have proved their contention five weeks ago that Townley was acting on CIA orders when he killed Letelier. But the defense attorneys suggested that Townley's contacts with the CIA in the early 1970's left open the possibility. "There are enough unanswered questions there," Dubin argued. "There are enough gaps of reasonable doubt here. You could drive a truck through the holes in this case."

Ross and codefendant Guillermo Novo Sampol are charged with the Letelier and Moffitt murders as well as other offenses. Guillermo Novo's brother Ignacio Novo Sampol is charged with lying to a grand jury investigating the Letelier slaying and failing to tell authorities about the crime.

The jury is expected to start deliberating today after the government makes its rebuttal of defense contentions and Judge Parker gives the jurors legal instructions.