Sylvie Cachay Update: Swimsuit designer's e-mails on display in Nicholas Brooks' murder trial

(CBS) NEW YORK - E-mails between Sylvie Cachay and her three best friends were presented in court Tuesday during the murder trial of Nicholas Brooks, a songwriter's son who is charged in the 2010 death of Cachay, his swimsuit designer-girlfriend, CBS New York reports.

PICTURES: Sylvie Cachay: Fashion designer found dead in posh NYC hotel

The 33-year-old Cachay was found dead in an overflowing bathtub in a room at the SoHo house, a posh New York City hotel, on Dec. 9, 2010.

According to the station, Cachay documented the ups and downs of her relationship with Brooks in e-mails to her friends, at times referring to him as "the kid I'm dating," as her "man-boy" or as a "stoner" who quit his job in a cupcake shop and had no desire to work anywhere.

In the e-mails she reportedly complained that his drinking, drug use and late night partying were bringing her down.

Cachay had been determined to revive her swimsuit line after the financial crisis shut it down, the station reports.

It was also disclosed in court Tuesday that in early December 2010, the week before Cachay's death, Brooks, now 26, showed her a website that he was allegedly using to hire prostitutes, according to the e-mails. That was the final straw and Cachay was determined to break-up with him, the e-mail detailed.

Prosecutors say Brooks used Cachay to fund his lavish lifestyle and marijuana habit and when she allegedly threatened to cut him off, he killed her.

Brooks' lawyer, Jeffrey Hoffman, said authorities "rushed to judgment" by arresting his client in the high-profile killing. He has pleaded not guilty.

Hoffman denies the allegation that his client drowned the swimsuit designer and argues that Cachay may have been heavily medicated and slipped in the tub, CBS New York reports.

According to the station, the medical examiner determined Cachay died from strangulation and drowning.

The trial is expected to last through the beginning of July.

Complete Coverage of Sylvie Cachay on Crimesider