Rob Reiner and his wife, Michele Singer Reiner, were found dead in their Los Angeles home on Sunday, Dec. 14

Jane Fonda revealed she spent time with the couple the day before they were killed in a tribute shared on Instagram

“I saw them night before last looking healthy and happy,” she said. “I am reeling with grief. Stunned”

Jane Fonda is recounting the final moments she spent with Rob Reiner and his wife, Michele Singer Reiner.

On Sunday, Dec. 14, Rob, 78, and Michele, 70, were found dead by apparent homicide at their home in Brentwood, Calif. Their son, Nick, is now being held without bail at Los Angeles' Twin Towers Jail, having been arrested on murder charges in connection with their deaths.

Fonda, 87, shared a photo of the late couple on Instagram alongside a tribute recalling her time spent with them shortly before they were killed.

“Rob and Michele Reiner were wonderful, caring, smart, funny, generous people, always coming up with ideas for how to make the world better, kinder,” she wrote on Dec. 15.

Fonda said the When Harry Met Sally director and his wife had recently been helping her to relaunch the Committee for the First Amendment, a group that champions freedom of expression from government censorship.

“I saw them night before last looking healthy and happy,” she said of Rob and Michele. “I am reeling with grief. Stunned.”

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Rob and his son, Nick, allegedly got into a “very loud argument” on Saturday night while attending a Christmas party hosted by Conan O'Brien, PEOPLE previously reported, citing multiple sources.

“Nick was freaking everyone out, acting crazy, kept asking people if they were famous,” said one of the sources.

Rob and Michele left the party after the alleged heated exchange, according to TMZ.

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The couple was then found dead in their home a day later, when the Los Angeles Fire Department was called to provide medical aid at around 3:30 p.m. local time.

Rob and Michele had three children together: Jake, Nick and Romy.

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Having been identified as a suspect, Nick was located by police near the campus of the University of Southern California after allegedly leaving his parents’ Los Angeles home, ABC News reported. 

“We have our robbery homicide division handling the investigation. They worked throughout the night on this case and were able to take into custody Nick Reiner," said LAPD Chief Jim McDonnell, per the outlet.