IRVINE ( — A memorial service will be held Sunday at Concordia University in Irvine for Monica Quan and her fiance Keith Lawrence.

Authorities believe Quan — a Cal State Fullerton women’s assistant basketball coach — and Lawrence were murdered by fired Los Angeles Police Department Officer Christopher Dorner.

READ MORE: Garcetti: 88,000 Vaccines To Be Given Out During The Week At City Sites

Quan and Lawrence met when they were students and basketball players at Concordia University.

Sunday’s service (scheduled for 11 a.m.) is ” going to be extremely tough,” said Tim Preuss, Concordia’s dean of arts and science. He met the couple when he was the university’s athletic director.

“Monica and Keith were both great students, great leaders and both were really talented athletes as well,” Preuss said.

“They were widely known, dearly loved. We’re still trying to wrap our heads around this senseless tragedy that took them so quickly and unexpectedly.”

Quan started her coaching career at Concordia while working towards a master’s degree in coaching and athletic administration.

Most first-year coaches lay low, but that wasn’t Quan’s style, Preuss told City News Service.

“Usually a new-kid-on-the-block young coach stays in the background,” Preuss said. `But that wasn’t Monica. She wasn’t a pushy person, but she was really intense.”

READ MORE: 'I Was Desperate': Prince Harry And Meghan's Bombshell Interview

Assistant coaches usually stay seated during a game, but Quan was often on her feet, Preuss said.

He also recalled the time Lawrence “made an incredible 3-point shot to extend a game into a fourth overtime, which we ended up winning.” A clip of that shot on YouTube was often played on TV newscasts following the couple’s Feb. 3 slayings.

“He was just one of those people who was a fierce competitor on the court, but off court he was so friendly, so genial,” Preuss said.

Although they were star athletes they didn’t act like it, Preuss said.

“A lot of time you get star basketball players –and it doesn’t matter the size of the university — they’re so full of themselves,” Preuss said.

“But that was never Keith. He was always approachable, humble and kind.”

Preuss also fondly remembered how Quan’s parents would attend all the team’s games. Her mother would cook a big meal for the team once a year, he said.

Quan, 28, and Lawrence, 27, were found shot to death in his parked car. Police suspect it was a revenge-killing. Quan’s father, a retired LAPD captain, represented Dorner at a Board of Rights hearing that ultimately led to his firing.

MORE NEWS: Woman, Child Found Dead Inside Rancho Cucamonga Home

(©2013 CBS Local Media, a division of CBS Radio Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Wire services contributed to this report.)