Rackauckas had tweeted that law enforcement was seeking potential additional victims Tuesday.
Prosecutors have also expanded their timeline into alleged rapes dating back 20 years, CNN reported.
In a statement to the Los Angeles Times, Robicheaux and Riley “unequivocally” denied the allegations of non-consensual sex.
Investigators have found more than 1,000 videos and photos on the surgeon’s cellphone, prosecutors said. Women in the videos were in various states of consciousness, officials said.
The two were charged Sept. 11 with several felonies. A few of those charges were rape by use of drugs, oral copulation by anesthesia or controlled substance, and assault with intent to commit sexual offense with two women coming forward with accusations.
One of the women said she met the couple at a boat party in April 2016, and a blood sample later tested positive for multiple controlled substances. The other accuser told police she was taken to Robicheaux’s apartment six months later after a night of heavy drinking.
A search of the Robicheaux’s home found illegal drugs, including the date rape drug GHB, Rackauckas said.
Riley and Robicheaux were released from jail Monday on $100,000 bail.
Robicheaux was named Orange County’s “Most Eligible Bachelor” by Orange Coast Magazine in 2013. He is also known for appearing on the reality program “Online Dating Rituals of the American Male,” which aired on Bravo in 2014.
The district attorney said the couple looked like “clean-cut, good-looking people,” but colluded to seduce and assault women they met at bars and local festivals.
Investigators believe the couple also met some women through dating apps such as Tinder and Bumble.
“People often assume that rapist are creepy, scary men who lunge out from hiding among bushes and attack unsuspecting women,” Rackauckas said at a news conference earlier in the week. “The reality is that rapists come in all socioeconomic groups, any background.”