The trial of a Lanham businessman charged with attempting to murder a D.C. police sergeant with a machete opened in Prince George's County Circuit Court yesterday with conflicting stories about the July roadside incident in which the Lanham man was shot three times by the policeman.

"Somebody is not really telling this incident as it happened," defense attorney William Brooke told the jury, an apparent allusion to D.C. Police Sergeant Joseph C. Gentile, who acts as spokesman for the department.

During the incident, according to court testimony, Gentile shot Patrick Brogan, 38, the owner of a Lanham courier service, in the arm, chest and back. Gentile, who was off-duty and had been driving his personal car, was not injured.

The incident began while the two were driving west along Rte. 450 near Bowie. Brogan, according to his lawyer, believed that Gentile was tailgating him and that Gentile had made "very critical and offensive gestures" to him as he passed by in his car. As a result, according to Brooke, Brogan did a "foolish" thing. He began following Gentile's car and then got out of his car, holding a machete he had used earlier to clear weeds.

Gentile also got out of his car and was holding a gun.

According to Brooke, Brogan "indicated that he wished to surrender" by raising his arm with the machete. At that point, according to Brooke, Gentile began firing at Brogan.

But Gentile, who took the witness stand yesterday before Judge Jacob S. Levin, told a different story. He said that Brogan "looked at me and said 'Now you'll get yours' and swung his machete."

Gentile said he ducked and ran across the street. "I kept picturing having this man hack me to death with a machete," Gentile related. "I said 'Stop,' and he said, 'Now I'm going to kill you,' and he lunged toward me. I was totally terrified and that's all I remember."

In his first statement to police, Gentile said he was about 10 feet away from Brogan when he fired the shots. Yesterday however, Gentile testified that Brogan was about two feet away from him and that Brogan swung the machete over Gentile's head.

The defense has concentrated on inconsistencies between the physical evidence and Gentile's statements to police.

For example, Brooke said Gentile told police that Brogan began hitting Gentile's car with his machete. But an examination of Gentile's car by police produced no evidence that the car had been hit.

Brogan had been celebrating his birthday prior to the incident and had been drinking champagne and rum with friends, according to court testimony. He also had snorted some cocaine, James Northern, a friend who had been with Brogan, testified yesterday.

Gentile testified that he had consumed less than a glass of wine before driving home from Washington, where he had been visiting a friend after work.

Brogan had a machete with him because he had lost his dog and often went looking for him in areas of thick brush, his attorney said. Brooke said his client suffered extensive injuries after being shot by the police sergeant and only recently returned to work.

The trial is expected to continue throughout the week.