A Lancaster man pleaded not guilty Monday to murder and arson charges stemming from the death of a woman — believed to be his girlfriend — whose charred body was found in the trunk of a car in the Quartz Hill neighborhood of Lancaster.

Matthew Switalski, 37, was charged Dec. 26, 2023, with one count each of murder and arson of an inhabited structure in connection with Veronica Aguilar’s Dec. 20 death.

Authorities said late last year that the cause of the 27-year-old woman’s death was deferred pending further investigation.

Switalski was arrested Dec. 21 in Kern County, authorities said. He has remained behind bars since then, jail records show.

Sheriff’s officials said Switalski owns the home on the 41400 block of 38th Street West where the body was found around 8:30 a.m. Dec. 20, when fire crews extinguished a fire in the garage.

Aguilar’s body was found in the trunk of a car that was parked in the garage, sheriff’s officials said.

ABC7 reported that neighbors reported hearing a woman’s “bloodcurdling” scream, followed by an explosion and then the fire, hours before Aguilar’s body was discovered.

The victim’s family said Aguilar was a UCLA graduate and elementary school teacher.

“My little sister Veronica was taken from us on December 20, 2023 (and) her story is all over the news of her brutal death,” her brother, Juan Aguilar, wrote on a GoFundMe page that raised more than $27,000. “Things will never be the same ever again. We miss her so much. She had the best spirit, she always had a smile. My family is heartbroken.”

Switalski is due back in a Lancaster courtroom March 27, when a date is scheduled to be set for a hearing to determine whether there is sufficient evidence to allow the case against him to move forward to trial.