Nicholas Brooks pleaded not guilty to attempted murder of his girlfriend Sylvie Cachay when he faced a judge yesterday morning. But prosecutors say that the 24-year-old killed the fashion designer because she wanted to break up with him but "the defendant did not accept that reality" and that a "letter of apology" from Brooks was found in Cachay's room.

Cachay's partially clothed body was discovered submerged in a tub at the Meatpacking District's Soho House on Thursday morning, a few hours after the couple checked into the exclusive club because of a fire and fight the pair had in Cachay's West Village apartment. While the ME's office's initial findings have found no conclusive cause of death, the police are treating the case as a homicide.

Hotel staff found Cachay's body around 3 a.m., after another guest complained about leaking water (the water was running in the tub), and Brooks allegedly left Soho House at 2:30 a.m. and came back at around 3:30 a.m., only to be taken to the police station for questioning. Brooks' lawyer Jeffrey Hoffman said, "I’m convinced he is innocent and didn’t commit any crime," and said his client only found out Cachay was dead from the police, "No one was more shocked than he was that after 18 hours he was charged with a crime. The last time he was with Sylvie she was alive and healthy."

However, Manhattan assistant district attorney Jordan Arnold "said Brooks was a flight risk with a history of violence and a rocky relationship with his relatives," according to the Post. Arnold also said that Brooks, whose father, an Oscar-winning songwriter, is accused of sexually assaulting and raping numerous women in NYC, had a questionable history:

"There are domestic incidents on file with his family," said Arnold, who plans to convene a grand jury to hear the charges against Brooks.

Brooks also had an altercation with an unknown woman last Christmas Eve, Arnold said. Brooks pushed the woman to the ground and told her, "You’ll be dead in 48 hours," according to the ADA.

No arrests were made but police were aware of the incident, Arnold said.

He described Brooks as a rootless rich kid who lives off a trust fund and has no deep ties to keep him in town.

"He sleeps on a mattress in a rented room. His possessions are in a suitcase. The defendant attempted to kill a young woman who had everything to live for," Arnold said.

Cachay's cousin told WCBS 2 that the family is "all thinking that [Brooks] was responsible for her death."