Divers spent most of the day searching a nine mile stretch of the river using sonar and K9s, but so far they haven't found 37-year-old Hubert "Doug" Carrillo.
Authorities say Carrillo fled from police by intentionally jumping into the river early Wednesday morning.
The incident started around midnight when Fayetteville Police received a report about an armed robbery at a Kangaroo convenience store in the 4000 block of South Main Street in Hope Mills.
About 30 minutes later, an officer spotted a vehicle matching the suspect's description.
When authorities stopped the teal Ford F-150 near the Fayetteville Police Department's Training Center on North Eastern Boulevard, police said a woman jumped out of the vehicle, and the driver sped off. ABC11 has learned the woman, Brandy Baker, was the suspect's girlfriend.
Baker said Carrillo had just picked her up for a trip to Walmart when police stopped them. Baker said she did not know what happened, but when Carrillo drove off, she jumped out because she knew something was wrong.
"I had to get out," Baker said. "His last words to me were 'I love you.' I looked at him and said 'I love you, too' and I jumped out of the truck."
Carrillo then led police on a chase to a dead end near his Medina Road home before jumping out of the vehicle. He then ran into a wooded area, and officers chased after him. During their search, police said Carrillo intentionally jumped into the Cape Fear River.
Two officers jumped into the river in an effort to save Carrillo, but were unable to reach him.
"They are doing sonar scans. I know divers have been in the water as well, and we will continue those efforts until they hopefully locate the suspect," said Fayetteville Police Lt. Todd Joyce. "For the sake of the family, we would hope the suspect is still alive but as it was stated by the chief yesterday, the officers did see him go down in the water three times as our officers were still trying to get to him. So, unfortunately we have to look at the reality that he could have drowned."
Meanwhile, detectives with the Fayetteville Police Department are investigating additional robberies that have been associated with Carrillo.
Baker told ABC11 that, "We knew it would come to this" -- saying Carrillo had been unemployed for months and was depressed.
"He lives his life dangerously, that's what he does. He's an outlaw," she said. "We just hope and pray they find his body."
Baker also said Carrillo had spent most of his life in prison and that he had said he'd rather die before going back.
According to the North Carolina Department of Justice's website, Carrillo was convicted in 1998 and 2011 for indecent liberties with a minor. He is currently a registered sex offender.
The search for Carrillo will resume Friday morning.