A 26-year-old woman was found murdered in her Chelsea apartment by her sister last night, and the murder victim's boyfriend--and the murder suspect, according to police-- killed himself a few hours after the discovery.

Margaux Powers's family had been worried they didn't hear from her for a few days, so her sister Dana went to Margaux's apartment at 235 West 22nd Street on Friday night. Doorman Constantine Ionescu accompanied Dana to the apartment, and the Daily News reports though they found Powers' cellphone, "the apartment appeared orderly and there was no odor...But they did not think to check behind the closed bathroom door."

Then last night, Dana Powers returned with friends and they, with Ionescu, checked the apartment at 6 p.m., this time checking the bathroom and found Margaux's body under a green blanket. Ionescu said Dana was distraught, "She said, 'No! No! It's not possible. Tell me it's not true!'...I just saw some hands... I didn't want to look. I didn't see her face. When I saw the girl, I prayed." It's unclear when Powers was killed--her throat was slit and her body was "chopped into pieces."

The News says police "found a written apology from the murderer in the apartment, but the note was unsigned," and started to search for Powers' boyfriend Jonathan Smith, who also lived in the Chelsea apartment. From the News:

While police swarmed the Chelsea building, Smith was downtown, where he jumped from an apartment house at 15 Broad St., landing on Exchange Place in two pieces, cops said.

"I was walking with my girl. Somebody just fell off the building," said a stunned Chao Williams, 21, of East New York, Brooklyn. "I just heard the noise. It was like a loud boom."

Ionescu said that Powers and Smith "fought all the time" and a friend of Dana Powers said, "They used to fight. I heard he had a bad temper. He was a little crazy."