The man who was arrested after a string of fires left historically black churches gravely burned is now facing hate crime charges.

Holden Matthews was arrested Wednesday after investigators tied him to three church fires that spanned a 10-day period in Louisiana's St. Landry Parrish.

Matthews, the 21-year-old son of a sheriff's deputy, appeared in court in Opelousas on Monday. He entered a not guilty plea via his court-appointed lawyer.

The Associated Press reports Matthews did not speak during the hearing, which came after prosecutors filed papers to add three charges accusing Matthews of violating the state's hate crime law. Those three charges come in addition to three charges of arson of a religious building that Matthews already faced.

Matthews was denied bond on Monday, which law enforcement officials pushed for because they view him as a continued threat.

"We felt that he was an immediate risk to public safety," said Louisiana Fire Marshal Butch Browning, according to the AP.

"In my mind, I felt another fire was imminent," Browning said in court Monday.

Browning made similar sentiments shortly after apprehending Matthews. During a news conference on Thursday, Browning said officials were still working to determine his motives, but added they found that Matthews had ties to "black metal and its association and history with church burnings in other parts of the world."

Black metal, a distant genre of devil-worshipping death metal music, has roots in the Norwegian heavy metal scene that reportedly was the inspiration for several church burnings in the country in the early 1990s.

Matthews' father, who works for the local sheriff's department, was present at Monday's hearing. The AP said the suspect's parents watched from a video conference of the courtroom, and at one point his father was seen leaving the room in tears.

The three fires investigators tied Matthews to were all near the town of Opelousas, and no one was hurt as no one was inside any of the structures at the time of the blazes.