Roy Kipp took the stand at his capital murder trial Wednesday and told jurors he was acting in self-defense when he gunned down his wife and her lover.

The retired Collier County, Fla., sheriff's lieutenant testified that he was dismayed after interrupting a tryst between his wife, Sandy, and his friend, sheriff's deputy Jeff Klein, but only fired his gun after Klein aimed a weapon at him. He claimed he shot his wife by accident after she ran in front of him.

But on cross-examination, Kipp appeared to stumble. Under a tough grilling by prosecutor Marshall Bower, he claimed he had no memory of several incriminating conversations, including confessions he allegedly made to his brother and another friend hours after the killings.

"Let me get this straight, you can remember the traumatic events of what happened in that apartment, but you can't remember a conversation several hours hours later," Bowers said.

"That's correct," Kipp answered.

The 45-year-old faces death row if convicted of first-degree murder in the May 20, 2000, shootings in Naples. Closing arguments are scheduled for Thursday morning.

Relatives of the victims and the defendant packed Judge Daniel Monaco's courtroom in Punta Gorda during the hour Kipp spent in the witness chair. First tearful and later combative, Kipp denied nearly every aspect of the prosecution's theory that he killed the pair after learning his 35-year-old wife had moved out of the family home and began a relationship with Klein.

Taking the stand on the heels of eight defense witnesses — neighbors and other acquaintances who described the Kipps as a normal, loving couple — Kipp denied his wife was trying to leave the marriage. He acknowledged she had recently rented the temporary apartment where the killings occurred, but claimed the apartment was only a quiet place away from him and their 8-year-old daughter, Danielle, to study for night classes, not a new home.

On the night of the shootings, he said, his wife went to the apartment to do some work and told him she would return home to sleep. When she did not return, nor answer the apartment phone or her cellphone, he became worried, he said.

"Something was wrong in my mind that she wasn't answering the phone," he testified, adding that in January a strange car had followed his wife home on two occasions. He said he put his 9 mm gun in his pocket and drove to the apartment.

Kipp said lights and the television were on inside, but no one answered the door. His suspicion further raised, he went to the backside of the apartment and looked through a window, he said. He saw a woman's shape and shortly thereafter the outline of a man's head, Kipp said.

"I was going in that apartment to find out what was wrong," he said.

He climbed onto a lanai, breaking through a screen, and entered the apartment. Inside, he said, he saw his wife in her panties and a man scrambling to pull up his pants. When the man turned, Kipp said, he saw it was his friend Klein.

"I said, 'You!' and he said, 'What the f**k are you doing here?'" Kipp said. He testified that he stammered out a few more words, including "What would the sheriff think?" before Klein disappeared into the rear of the apartment. He turned to his wife for an explanation and "she said, 'You wouldn't understand, Ray. It's not what you think.'"

Moments later, Kipp said, Klein emerged from a back bedroom with a gun. Investigators testified for the prosecution that Klein's weapon was found in a fanny pack locked in his truck some 250 feet from the apartment, but the defense has repeatedly suggested officers moved the weapon to make Kipp look more culpable.

"And he pointed it at me," said Kipp. "As soon as I saw the gun, I reacted immediately ... and I shot him." Klein never fired, he said.

Kipp said his wife ran in front of him as he continued firing. The medical examiner testified Klein was struck by eight bullets and Sandy Kipp, a single shot to the back.

When he stopped firing, Klein said, "I looked over to my right and saw Sandy on the ground outside the front door."

He said he held her hand and checked for a pulse, but felt none.

"It happened so fast it was like it never even happened. I'm going to go home and this is going to go away," Kipp recalled thinking. Several hours later, he was arrested.

On cross-examination, prosecutor Bowers ridiculed Kipp's account of the actual shooting, saying it did not match blood evidence from the crime scene. If Sandy Kipp was shot in the apartment, rather than outside as she tried to escape, why was there no blood on the carpet, Bowers asked.

Kipp said he did not know, but refused to look at crime scene photos showing his wife's body crumpled around a large pool of blood.

"I'm not going to look at that picture. I'm sorry," he said.

Bowers confronted Kipp with the testimony of star prosecution witness Peter Lewkowicz, a friend and coworker of Kipp. Lewkowicz told jurors earlier this week that Kipp had long suspected his wife was cheating with Klein and was crushed when she announced she was moving out of the family home a few days before the shooting. Lewkowicz said Kipp called him three hours after the killings and said he had tracked his wife to her new apartment, found her with Klein and "waxed 'em" both.

In that confession, Lewkowicz testified, Kipp said he killed Klein, then shot his wife because she was screaming and threatening to call police and then returned to Klein's fallen body to deliver a final shot in his back. He never mentioned Klein having a gun, Lewkowicz said. It was Lewkowicz who first alerted police to the shootings.

Kipp repeatedly said he had no memory of his conversation with Lewkowicz, and said the man's testimony was untrue.

"How do you explain that what he said so closely matches the crime scene?" Bowers asked.

"I don't know," Kipp said.

He also claimed to remember only parts of a conversation with his brother Billy an hour after the shooting. Billy Kipp testified that his brother said he shot "Sandy and her boyfriend," and asked to borrow a car to leave the area undetected. Billy Kipp also said Roy Kipp never mentioned Klein's gun.

"You've got a selective memory here," Bowers said to the defendant.

Roy Kipp said he could only vaguely remember a conversation with his wife's sister, Wendy Postan, a week before the shooting. She testified that he asked her about his wife's "boyfriend" and said he would kill her if he ever discovered an affair. On the stand, Kipp denied making that threat or a similar one to his wife's cousin.

After his testimony, the defense rested its case. One by one, members of the victims' families approached prosecutors Bowers and Amira Dajani Swett and embraced them.

The trial is being broadcast live on Court TV.