Energy Drink Killing: Brother Says Plea Is Bull

June 3, 2011— -- The brother of alleged "Red Bull" killer Stephen Coffeen told a Florida court this week that his brother was perfectly sane when he visited his father in St. Petersburg in 2009 and smothered the 83-year-old World War II veteran and writer with a pillow.

The case made national headlines earlier this year when five psychiatrists said Stephen Coffeen had become temporarily psychotic after not sleeping and drinking the caffeinated energy drink Red Bull.

"It was a combination of factors, but Red Bull is the one that is sexiest," defense attorney Peter Sartes said. "The caffeine had an impact on other things."

Thomas Coffeen, 46, insists that his brother, 42, has never exhibited any signs of mental illness and his motive was sibling rivalry.

"He was jealous of me," he said. "I was always the more successful one. I had a family, he didn't. He came down here after 11 years and he meant to do harm to my father."

Now, the state, in agreement with the defense, has asked Pinellas County Judge Nancy Moate Ley to rule that the defendant is not guilty by reason of insanity, which is seldom granted, especially in Florida's courts.

Her decision is due Wednesday, according to defense attorneys, who say they know more about Stephen Coffeen's mental state than his brother does, but cannot disclose additional findings because of privacy laws.

"Part of his psychosis was that he may have imagined a self-defense situation," defense lawyer George Tragos said. "The police report shows that even the brother on the day of the incident said my client was acting crazy."

He also said that Thomas Coffeen "has certainly not been acting like you would expect a brother to act," and speculated that the father's will might have triggered some rivalry on his part.

Thomas Coffeen told ABCNews that he was on vacation with his wife and four children at Disney World, when his brother, who was visiting from California, begged him to return home, then claimed he had killed their father in self-defense.

In the week prior to the killing, the brothers had been making arrangements to get nursing care for their elderly father, a former English professor who was "sharp as the day is long," but needed assistance.

"We were never that close growing up," he said. "He was always concerned that my parents gave me preferential treatment. But I never saw this coming."

Thomas Coffeen lives in Tierra Verde, Fla., and works in the resort industry and the defendant is an IT specialist from Davis, Calif. "I had four children and he was jealous of my situation," he said. "I started my own company and did a lot of things he wished he could have done."

He said the boys were never treated differently. "My father was the most fair, down-the-middle guy," Thomas Coffeen said. "[Stephen] felt he was never a success even though his education was superior to me."

As for their father, Robert Coffeen, "He was brilliant and had the highest doctorate in English," his son said. "He was a good writer and a painter and a great grandfather to my children. This was a horrible thing to happen."

The defendant was visiting his father for the first time in 11 years, according to his brother. Both father and son were staying at Thomas Coffeen's Tierra Verde home when the killing took place.

Stephen Coffeen arrived in Florida on a red-eye flight Dec. 12, 2009, according to his brother. They spent most of the week making plans to get assistance for their father, a devout Christian Scientist, who used a walker.

"He was up in age, but his mind was there," Thomas Coffeen said. "He was walking a little slower so we thought maybe we would get him a part-time nurse or put him in a nursing home during the week."

The brothers were working with lawyers to secure powers of attorney to pay bills and make other arrangements and were "amicable the whole time," according to Thomas Coffeen. "We had no arguments."