PHILADELPHIA - Former hippie guru Ira Einhorn, who once described himself as a planetary enzyme, took the witness stand at his murder trial on Monday to deny killing his girlfriend Holly Maddux in a fit of rage 25 years ago.

In a packed Philadelphia courtroom, a smiling but sometimes nervous-looking Einhorn told jurors that his stormy romance with the 30-year-old Bryn Mawr graduate never reached full flower because of his rampant appetite for other women.

"I think we loved each other very much. But we had a very difficult time creating the context in which our love could flower," said the counter-culture leader who helped launch the annual Earth Day observance in 1970.

"She got increasingly dissatisfied with the fact that I was sleeping with other women," he said, during four hours of direct testimony. "She had increasing difficulty with that."

When Einhorn's lawyer William Cannon asked if he was responsible for Maddux's death, the radical who was once known as "the Unicorn" turned to the jury, and without hesitation, said: "No, I did not kill Holly Maddux."

The grisly story of the Maddux murder has already been told in the true-crime book, "The Unicorn's Secret: Murder in the Age of Aquarius," and on numerous television programs including an NBC mini-series.

Maddux, a blond Texas cheerleader who lived with Einhorn for five years in a West Philadelphia apartment, disappeared on Sept. 11, 1977, after trying to break off her relationship with the radical luminary whose friends and associates included yippies Jerry Rubin and Abbie Hoffman.

Police discovered her mummified remains 18 months later in a steamer trunk stored in his closet, and charged Einhorn with bludgeoning Maddux to death so savagely that fragments of her skull were later found in her brain.

"When I finally found out it was Holly, I broke up for days. It ripped me to pieces," said Einhorn, who maintains that Maddux walked out of his apartment and never came back but phoned a few days later and made a promise to stay in touch. "She never lived up to it," he said.

"Having Holly's name cross his lips, that really did anger me," Maddux's sister Meg Wakeman of Seattle later told reporters outside the city courthouse, which remained open during the Columbus Day holiday solely for the Einhorn trial.

After his arrest in 1979, wealthy patrons rallied around Einhorn. His first defense lawyer was Arlen Specter, a former Philadelphia district attorney who now serves as a Republican U.S. senator from Pennsylvania.

EINHORN JUMPED BAIL

But Einhorn jumped bail in 1981 and spent 20 years on the run in Europe. Meanwhile, a 1993 jury convicted him in absentia of Maddux's slaying and sentenced him to life. The Maddux family also won a wrongful death verdict to stop him from selling his story to a publisher or Hollywood studio.

Einhorn was discovered living in France with his Swedish wife, Annika, who has avoided his three-week trial for fear of arrest. He was finally extradited to the United States on July 20, 2001, after the Pennsylvania General Assembly passed a law granting him a new trial and U.S. authorities promised he would not face the death penalty.

With his white hair and mustache neatly trimmed and sporting a tie and jacket, Einhorn treated the six men and nine women of the jury to four hours of direct testimony.

He traced his life from Philadelphia childhood to his career as guru to an elite group of more than 300 people who he said included an Iranian prince, a member of Europe's Rothschild family and executives of the former Bell Telephone.

Einhorn and his lawyer side-stepped his longstanding claim that the CIA framed him because of his Cold War research into the Soviet Union's use of psychic phenomena as weaponry.

But he did admit to having violent encounters with two women in the 1960s, one of whom claims he struck her with a bottle and tried to choke her. He told jurors he later underwent therapy with the then-experimental drug, Ecstasy.

"I felt as if the demon was under control," he said. "The energy exists. I had to deal with it and I learned to deal with it."

Cross-examination was due to begin on Tuesday.