A trial began Tuesday for a case involving the murder of a UCLA student in 2015.

County prosecutors accused Alberto Medina, a former Fresno State University student, of the murder of Andrea “Andy” DelVesco, a UCLA student, in her Roebling Avenue apartment on Sept. 21, 2015 during a trial Tuesday. Medina was also charged with burglary and arson after allegedly torching DelVesco’s apartment and stealing items from an apartment across from hers.

An autopsy found DelVesco most likely died from multiple stab wounds in the upper-body region.

Victor Avila, the deputy district attorney prosecuting the case, said the county is trying Medina for five separate charges: one count of murder, one count of arson, two counts of burglary and one count of cruelty to animals, since DelVesco’s dog sustained terminal injuries from the fire that prompted her family to euthanize him.

Medina had previously been tried with Eric Marquez, a former UCLA student, when the two were arrested in connection with DelVesco’s murder in 2015. However, after the counsel for both defense and prosecution permitted the separation of Marquez from the trial, he plead guilty to first-degree residential burglary and accessory after the fact in December. Medina, however, plead not guilty to his charges.

[Related: Full coverage of the DelVesco murder trial since 2015]

In the first day of court proceedings Tuesday, the prosecution called several witnesses to provide testimony.

Sarah Muhr, who was a UCLA student at the time of the incident and lived above DelVesco, said she had just returned home from dropping her boyfriend off at the airport when she noticed a man matching Medina’s description standing near the second or third step on the staircase leading to her apartment front door.

Muhr first called the police because she thought the man was suspicious and officers briefly investigated the courtyard area, appearing to Muhr to flash their lights in windows before leaving without letting her know they did not find anything.

During the officer’s search, Muhr texted one of the women who lived on the ground floor near DelVesco but she did not respond. Attempts to call DelVesco were automatically sent to voicemail, Muhr said.

As Muhr returned back to her room around 7 a.m., she heard a loud bang from downstairs. Muhr said she called the police a second time that morning when she saw smoke coming from DelVesco’s room and a man who looked identical to the one she had seen earlier ran outside. He now had a red blanket draped over his shoulders.

The prosecution played a recording of the 911 call, and jurors could hear Muhr calling out to DelVesco while on the phone with police dispatch. Muhr told the court she called from the balcony and chased after the man as he fled through the courtyard that connects to her apartment. By the time she reached the street, Muhr said she saw a red car with a fraternity decal on the rear window speeding away toward Landfair Avenue.

Conner Kirk, who was a Fresno State University student at the time of the incident and a member of the fraternity, recognized Medina’s car in a photo presented by the prosecution because of the Lambda Chi Alpha symbology stenciled on the rear window of the car. Muhr would later affirm this was the car that had fled the scene when smoke began emanating from DelVesco’s room.

Muhr said she identified the man as being light skinned and around 6 feet 1 inch or 6 feet 2 inches tall and 180 to 190 pounds. Although Muhr verified for Debra Werbel, Medina’s attorney, that she did not see the man’s face, she said she was confident the man was the same one she had seen near her the steps to her apartment earlier.

Prior to DelVesco’s murder, the prosecution holds that Medina stole several items, including a laptop and a set of speakers, from an apartment across the street from DelVesco’s apartment.

Mahir Shah, a UCLA alumnus who lived in the burglarized apartment, said he had gone to his girlfriend’s apartment the night of the incident and did not return until 6 p.m. the next evening. Avila presented Shah’s missing laptop and one of the stolen speakers as evidence during the trial, both of which Shah identified as his belongings.

The speakers require users to connect them online before they can be used. Shah said he thinks the speakers must be linked to an IP address, from which a person’s location can be tracked based on where they access the internet.

Avila said in his opening statement that Los Angeles police were able to use the location of the speaker to track the items Medina allegedly stole back to his apartment in Fresno, California.

When Werbel pressed Shah about whether the window to his apartment was open the night it was burglarized, Shah said he could not remember, despite earlier testimony during a pretrial hearing that the window could not close properly. Shah also admitted he only noticed his speakers and laptop were missing when his roommates informed him of the incident that morning.

The prosecution also requested testimony from medical and emergency officials who had responded to the fire.

Alfred Hernandez, a Los Angeles Fire Department fire captain at the time of the incident, said he arrived to the scene around 7:10 a.m. The firefighters entered the apartment through the front door and eventually reached DelVesco’s room, from which they could see a layer of smoke emanating.

Hernandez said the women outside had informed him DelVesco was still inside. He said they found her body on the bed resting near the headboard at 7:18 a.m.

Hernandez was able to make the determination that DelVesco could not be resuscitated, and she was pronounced dead around 8 a.m. after paramedics investigated her body.

Eric Jasperson, another responding fire fighter to the scene, said the room was completely burnt when he entered. He added fire officials also discovered DelVesco’s dog, barely breathing, near the foot of her bed at about 7:30 a.m.

Shay, a terrier mix dog, was admitted to the VCA West Los Angeles Animal Hospital around 8 a.m., said David Bruyette, who was medical director of the hospital at the time. The dog was immediately placed on oxygen because he struggled to breathe on his own, and he was heavily sedated with pain medication.

Bruyette said he offered euthanization as an option for Shay because it was clear to veterinarians he was not responding well to medical support.

Earlier, when Avila called DelVesco’s mother, Leslie DelVesco, to the stand, he asked her what she had decided to do with Andrea DelVesco’s dog after it was received by the hospital in critical condition.

“To let him go and be with Andrea (DelVesco),” she responded.

Medina’s trial is scheduled to last over the next few days as the prosecution and defense continue collecting testimony from witnesses. The trial will resume Wednesday.