The Upper Marlboro home where 17-year-old Amber Stanley was fatally shot. (Hamil Harris/Post)

Amber D. Stanley, a Prince George’s County honors student, started her senior year this week with aspirations of going to Harvard. Wednesday night, a gunman kicked in the front door of her house, climbed the stairs and shot her several times in bed.

Police think that the gunman set out to kill someone specific, walking straight to Amber’s bedroom, shooting and then fleeing without taking anything. But they don’t know whether he intended to kill Amber or whether he had gone into the wrong bedroom or even the wrong house.

Those who knew Amber said they could not fathom why anyone would want to harm the Charles Herbert Flowers High School student who tutored her peers and wanted to become a doctor.

“It is a tragedy when you lose someone with such potential,” said the school’s principal, Gorman Brown.

Police on Thursday revealed few details of the killing, saying only that the man kicked in the door of Amber’s two-storyChartsey Street house shortly after 10 p.m. and that he shot the 17-year-old multiple times. Three other people in the house escaped through a window and ran to a neighbor’s house, according to two law enforcement officials with knowledge of the case.

Amber D. Stanley (Credit: Prince George’s Public Schools)

“At this early stage of the investigation, we are exploring any and all possibilities,” said Julie Parker, a county police spokeswoman. She said detectives returned to the neighborhood Thursday evening to distribute fliers in the hope of turning up clues.

As word of Amber’s death spread among her friends, condolences and photos of the teen flooded social media sites.

Amber was studious and could seem shy at first, but those who knew her best said she had an outgoing and bubbly side. On her Twitter account, she described herself as a model and piano player.

“She was very popular among students,” said one of her former teachers, Lisza Morton-Wilson. “She was known for her positive attitude.”

Amber was enrolled in her high school’s elite Science and Technology Program, which admits the top 15 percent of county students. Morton-Wilson said that Amber was known as a peer leader and was part of a group that tutored other students.

Amber also loved to bake, and on Monday — the first day of school — she brought in a half-dozen chocolate cupcakes.

“They were great,” Morton-Wilson said.

Neighbors in Amber’s Kettering enclave of single-family homes said that Amber’s mother is a hairstylist in the District who was raising a foster child and also had two biological daughters. Amber’s parents could not be reached to comment.

Neighbors described Amber as a teen who kept to herself and seemed focused on her studies. “You would see her walking to the bus stop and coming home,” said a neighbor, TJ Vaughn.

Officers had visited the house last week for an issue involving Amber’s foster sister, according to law enforcement officials who spoke on the condition of anonymity because the investigation is just beginning. It was unclear whether that visit could have any link to the shooting.

Amber was active on Twitter, and her tweets included teen angst and joy about about classes, school schedule, friends and love interests: “Genetics class . . .I have a good feeling about it. I love that we can eat & drink.” And she engaged in some silly boasting: “I’m so cool I eat ice to warm up.”

Other times, she groaned about her mother being overprotective and bragged that her mother hadn’t found her Twitter account. Her tweets also complained about the foster childin the house.

On the first day of school, Amber posted a picture of herself in a white shirt, looking fresh and ready for class and smiling at several different angles into the camera. She wrote: “Yesterday \ First Day of Senior Year.”

Morton-Wilson said that Thursday was a difficult day for her, the students and teachers at Flowers. The school community is discussing how to honor Amber, she said.

Several students said they did not want to speak publicly about Amber, but when asked, one student gave a thumbs-up and said, “She was amazing.”

Staff researchers Magda Jean-Louis and Julie Tate contributed to this report.