A day after a daughter called 911 to report that someone had killed her mother, police identified the student who they said admitted to killing the respected psychiatrist over whom he had obsessed.

New Castle County police responded to the unit block of Withers Way in the Sanford Ridge neighborhood of Hockessin around 4 a.m. Wednesday to find 55-year-old Dr. Caroline Ekong dead. The house sits on a block of large single-family homes that border the Sanford School.

About half an hour later, police said a 21-year-old University of Delaware student called 911 and claimed responsibility for Ekong's death.

"We received a call from an individual who claimed responsibility for this incident and provided enough detail that we gave it attention," said Officer Tom Jackson.

Officers arrested Christopher Frick at the home he shares with his parents in the Autumnwood community, about a 10-minute drive from the crime scene. The 21-year-old University of Delaware senior, a mathematics major, faces murder charges in Ekong's death.

Investigators said Frick, who only had minor run-ins with the law before Ekong's death, broke into Ekong's home and stabbed her multiple times.

Ekong worked with young people as a psychiatrist at the Rockford Center, a behavioral health facility in Newark, Delaware. Investigators said Ekong knew Frick through "professional interaction" years ago but wouldn't say if she treated him.

An online review of the Rockford Center posted under the name of Christopher Frick calls the facility a "prison" and blames Ekong for his "imprisonment."

"On behalf of all of the staff at the Rockford Center, I extend our thoughts and prayers to the family during this extremely difficult time," the center said in a statement.

Police said Frick had planned the murder for a significant amount of time.

Ekong hadn't interacted with Frick in about three years, police said. He was, however, obsessed with her – unbeknownst to Ekong – prior to breaking into her home, according to investigators. Police said they found evidence of his obsession in his parents' house.

Frick faces first-degree murder, burglary and related charges and was held in county jail without bail.

It wasn't immediately clear if Frick had an attorney. No one answered the door at his parents' home Thursday night but police said they are cooperating with investigators.

Ekong's family asked for privacy and declined to comment on the case.