The daughter of a former U.S. director of national intelligence was charged with first-degree murder Friday amid allegations she stabbed an acquaintance in the neck in Rockville.

Sophia Negroponte, 27, was being held at the Montgomery County Detention Center in the killing of Yousuf Rasmussen, 24. According to charging documents, after stabbing Rasmussen, Negroponte yelled “I’m sorry,” removed the knife, and pleaded for him not to die. She is the daughter of John Negroponte, who in 2005 was appointed the nation’s first intelligence director by President George W. Bush.

“We love her deeply,” Diana Negroponte, Sophia’s mother, said in a brief interview Friday.

Sophia was one of five children the couple adopted in Honduras when John Negroponte served as a diplomat there in the 1980s.

“She was trying to live on her own and attend college,” her mother said. “And she has our total support.”

At about 11:15 p.m. Thursday, Montgomery County police said, they received a 911 call reporting someone had been cut in the throat inside a small apartment house, behind a larger home, along West Montgomery Avenue. Responding officers met the caller outside the home and directed them to the apartment.

As the officers walked in, according to a police affidavit filed Friday, they saw Sophia Negroponte laying atop a man covered in blood.

The man who called 911 told detectives he arrived at the apartment just before 10 p.m., noting both Negroponte and Rasmussen had been drinking, court documents said. He said he made a round of margaritas and the three watched television.

Negroponte and Rasmussen began bickering, the witness said, and at one point started wrestling on the floor, according to the police affidavit.

Then things cooled down, the witness said, and the three continued watching TV.

Rasmussen and Negroponte began arguing again, court documents said, before Rasmussen began digging through his backpack to search for his phone.

The witness said he saw Negroponte open a drawer to the right of the kitchen sink and pull out a knife covered with a sheath, according to court papers. The witness said he “saw Negroponte remove the sheath from the knife and lunge at Rasmussen in what [the witness] described as an ‘aggressive’ manner,” detectives wrote in their affidavit.

The witness said he saw Rasmussen with his arms up, saw the knife being directed toward his neck and saw Rasmussen fall to the floor with Negroponte on top of him, the affidavit said.

In their questioning of Negroponte, detectives wrote, she confirmed parts of the witness’s account. She said they had argued “over a silly issue,” calmed down, and then heated back up, court documents said.

“It was during this time that Negroponte advised that she only remembers removing a knife from Rasmussen’s neck and laying atop him yelling for him not to die,” detectives wrote.

She acknowledged that the third person in the apartment did not stab Rasmussen, detectives asserted, and acknowledged that she and Rasmussen had an altercation.

Negroponte had “stab/cutting wounds” on her right hand, detectives wrote, and police found a green-handled knife just outside the residence.

Dana Hedgpeth and Clarence Williams contributed to this report.