Nicholas Brooks pleaded not guilty Tuesday to second-degree murder charges in connection with the death of his ex-girlfriend during a court appearance in Downtown Manhattan.

Brooks, 24, was initially charged with attempted murder and strangulation in the death of fashion designer Sylvie Cachay, but the charges were upgraded at his indictment today. He has been remanded to jail.

The medical examiner declared Cachay's death a homicide last week, making murder charges possible.

Cachay, 33, was strangled and drowned, according to the medical examiner. Her body was found half-clothed and submerged in a bathtub at the SoHo House in the Meatpacking District on December 9.

In a written statement, Brooks told police he and Cachay checked into the hotel after a small fire in her apartment, but she was, in his words, "too pilled out" to sign in and had to be helped to their room.

Brooks writes that he ordered room service, but then went downstairs to eat, came back up and then left for drinks with a man he just met. When he got back he saw the police.

A lawyer for Brooks says Cachay was fine when Brooks last saw her.

"My belief, from what I know now, is that my client was not present in the premises when the young lady died," said Jeffrey Hoffman, Brooks' attorney.

Prosecutors argue that when Brooks left the hotel room, Cachay was already dead.

"There'll be very strong evidence to show that there was nobody in that room except Nicholas Brooks," said Susan Karten, a representative for Cachay's family. "He left the scene, as the [district attorney] says, after he killed Sylvie. He went to dinner and had drinks with a strange man after he had done such an act. So we're dealing with a cold-blooded killer."

Cachay's family members, who saw Brooks for the first time today, say Cachay repeatedly tried to end her relationship with Brooks at the time of her death.

"it was truly horrific and terrible to see this disgusting individual in the courtroom. And it was clear, obviously from the charges and his demeanor in addition, that he has absolutely no respect for anyone at all, or the law, or life, or my sister or my family," said Patrick Orlando, Cachay's brother.

When Brooks was being questioned by investigators, he was concerned about his safety in jail and his ability to make bail, according to the Manhattan district attorney's office. Officials also say Brooks' story changed several times during questioning.

Brooks is the son of Oscar-winning composer Joseph Brooks, who has legal troubles of his own and is charged with raping or assaulting a number of aspiring actresses.

If convicted, Nicholas Brooks faces between 25 years to life in prison.