When Herndon police responded to the killing of Alexander Alfaro Castillo in May 2018, new court documents say they found a chilling note perched on his chest next to photos of a young woman: “He raped me when I was drunk so I killed him.”

Alfaro Castillo, 40 of Herndon, had what appeared to be underwear stuffed in his mouth and the letters “MS” carved into his face, according to recently unsealed search warrants filed in Fairfax County court.

The bizarre scene was not the revenge killing it appeared to be, Herndon police said Tuesday, though they declined to offer a motive for the slaying because the case is still pending in court.

“The investigation did not reveal any supporting evidence that a sexual assault occurred,” Lisa Herndon, a Herndon police spokeswoman, wrote in an email. “Evidence left on the scene appears to have been left in an effort to distract and deter law enforcement investigative measures.”

The search warrants did confirm one aspect of the killing — the suspect charged with first-degree murder, Denis Castillo Hernandez, 21, is allegedly a member of MS-13, although police said the killing was not gang-related.

A white powder was sprinkled over Alfaro Castillo’s head and body when it was discovered, prompting officers to call a hazmat team to clean up the substance before detectives could investigate more fully, according to the search warrants. The powder was later determined to be a salt that was not dangerous.

Maria Ines Alfaro, the victim’s sister, said her family did not know Castillo Hernandez and they had not been told by police what prompted the killing.

“He was very sweet and supportive in many ways,” Ines Alfaro said of her brother. “He used to bring a bottle of wine to have with my mom and me. We used to do that every day.”

The court documents offer the first significant details about the case, which Herndon police had released little information about and received only brief mentions in the media last year. Police said the victim and the suspect were known to each other.

Herndon police responded to Alfaro Castillo’s mother’s home in the 400 block of Patrick Lane on May 26 for a report of a dead man, according to the search warrants. Alfaro Castillo’s body was in a downstairs bedroom. He was lying on his back on the floor in underwear and a black shirt.

The Virginia medical examiner said Alfaro Castillo died of multiple injuries.

Alfaro Castillo’s mother told detectives her son had received three to four phone calls on the night of May 24 at about 10 p.m., according to a search warrant. She heard her son tell an unknown caller “come pick me up at my mom’s house.”

In the early hours of May 25, other residents of the home said they heard a loud banging, screaming and Alfaro Castillo saying he hurt his head, according to the search warrants. The residents also told a detective they heard a conversation coming from Alfaro Castillo’s bedroom.

When the residents didn’t hear from Alfaro Castillo the next day, they entered his room and found him dead, according to the search warrants.

A detective later learned Alfaro Castillo had been texting with a contact listed as “Denis El Salvatruco” in the early morning hours of May 25, according to the search warrants. Cellular data also placed the phone that Alfaro Castillo had been texting with near the home of Alfaro Castillo’s mom. The phone number was later traced back to Castillo Hernandez’s father.

On May 31, Castillo Hernandez was taken into custody for a separate stabbing on that occurred on that date, according to the search warrants. Police officers found a picture of Alfaro Castillo in Castillo Hernandez’s wallet.

Castillo Hernandez was indicted in Alfaro Castillo’s killing in November and was arrested. He is scheduled to stand trial on July 8.

The search warrants in the case were filed to examine the home of Alfaro Castillo’s mother, Alfaro Castillo’s cellphone and the phone used by Castillo Hernandez. Castillo Hernandez’s attorney did not immediately respond to a request for comment.

Ines Alfaro said her brother made a living working at a Marriott hotel and various restaurants. She said her 18-year-old daughter got a tattoo on her back of an orchid, Alfaro Castillo’s favorite flower, in honor of him.

“My brother was the best uncle to them,” Ines Alfaro said.