The former roommate of Kristin Smart, a California college student who vanished more than 26 years ago, testified Monday in the ongoing trial against the two men accused in connection with her disappearance and presumed death, according to reports. 

Trial in the cases against Paul Flores, now 45, and his father, 81-year-old Ruben Flores, resumed on Monday after a brief break during the prior week. Paul Flores is accused of killing Smart while both were freshman at California Polytechnic State University’s San Luis Obispo campus on May 25, 1996. Her remains have never been recovered.

The trial proceedings are not televised or live-streamed, pursuant to a judge’s rulings. Local FOX 11 News was among reporters inside the courtroom for the day’s testimony.

On Monday, the juries heard from Smart’s roommate, Crystal Calvin, who now goes by the name Crystal Teschendorf. 

KRISTIN SMART TRIAL: CALIFORNIA JURY HEARS FROM FRIENDS ABOUT 'CREEPY' GUY AT PARTY ON NIGHT SHE VANISHED

In order of appearance Paul fLORES KRISTIN SMART RUBEN FLORES

This undated photo released by the FBI shows Kristin Smart, the California Polytechnic State University, San Luis Obispo student who disappeared in 1996. ((FBI via AP, File))

Teschendorf and Smart lived together in a dorm room in Cal Poly’s Muir Hall starting in February 1996, according to the reported testimony. Teschendorf moved in to the dorm with Smart mid-year, and said she and Smart knew each other, but "were not good friends." 

On the night Smart was last seen, Teschendorf said she and a friend who was visiting from out of town had spoken with Smart about her plans before they all parted way, according to the report. 

KRISTIN SMART'S CALIFORNIA TRIAL: JURY HEARS FROM MISSING WOMAN'S PARENTS, BROTHER IN LONG-AWAITED MURDER CASE

Smart and her friend, Margarita Campos, who testified earlier in the trial, had plans to attend a house party on Crandall Way, but Teschendork and her friends had planned to try other parties, according to the reported testimony. She said Smart was in a "good mood."

When Teschendorf left her dorm room at 8 p.m. that night, it was the last time she would ever see Smart. 

Teschendorf said she and her friend got back to the dorm room around 12 or 1 a.m., and she went to her boyfriend’s room while her friend slept in her bed.

The woman described how Smart usually brought a red-colored backpack and her keys with her when she stayed elsewhere overnight. But when Teschendorf returned to the dorm around 10 or 11 the next morning, Smart’s backpack was where she had left it the day before, the report said. 

CALIFORNIA KRISTIN SMART TRIAL FOR PAUL FLORES AND DAD BEGINS 25+ YEARS AFTER COLLEGE STUDENT'S DISAPPEARANCE

Teschendorf testified that it was "unusual" for Smart not to return to the room without telling anyone. According to tweets from inside the courtroom from the "Your Own Backyard" podcast, Teschendorf and other dorm residents mulled other possible scenarios as to why Smart might not have returned, but each possibility "started to feel less and less likely" as more time passed. 

Teschendorf called police on May 26, a Sunday, but said police would not create a report for her, according to the podcast tweets. That Tuesday, they notified police again after Smart was a no-show for her classes. 

"She had never done anything like that when she lived with me," Teschendorf reportedly testified. "It was very out of character for her."

KRISTIN SMART CALIFORNIA TRIAL JURIES TO HEAR FROM MISSING WOMAN'S FAMILY IN CASE AGAINST PAUL FLORES & FATHER

Paul Flores’ defense attorney, Robert Sanger, asked Teschendorf about whether she saw Smart drinking alcohol, to which she responded that neither she nor Smart had any alcohol while they were together, according to the reports. He also asked Teschendorf about her then-boyfriend’s roommate and friend, named Ted.

Sanger reportedly asked if Ted had visited her dorm room over the course of the weekend, to which she responded: "I’m sure he did. He came all the time. We were friends."

When asked about Ted’s whereabouts on the night of Smart’s disappearance, Teschendorf said he attended a party with them before going elsewhere, FOX 11 reported. 

Earlier in the day, the juries heard from San Luis Obispo County District Attorney's Office investigator James Camp, who attended Cal Poly around the same time as Smart and later became a D.A.’s office investigator. 

After Teschendorf’s testimony, the jury heard from Steve Fleming, a Cal Poly student-athlete who became friends with Smart and had lived in the same dormitory. Fleming’s testimony is expected to resume on Tuesday. 

The younger Flores is charged with murder in connection with Smart's presumed death. His father, Ruben Flores, is charged with helping his son bury Smart’s remains. He allegedly later unearthed and relocated the remains. 

Paul was allegedly the last person seen with Smart, who was said to have been intoxicated after they and others had attended an off-campus frat party over the Memorial Day weekend.

The state has said Paul Flores killed Smart in his dorm room while he tried to rape her when they were both freshmen. A massive search ensued.

"And while the entire community banded together to search for Kristin desperately, Paul and Ruben Flores did not join in," Deputy District Attorney Christopher Peuvrelle told the jury in his opening statements. "You will hear Ruben Flores would tear down missing posters of Kristin — tore down her smiling, beautiful face — called her a ‘dirty slut,’ all while her corpse was decomposing underneath his deck."

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Separate juries were selected from a pool of more than 1,500 Monterey County residents to oversee each case. The trial is expected to last four months.