Wyndham Lathem, 42, gave himself up late Friday at the Oakland federal building and Andrew Warren, 56, surrendered at about the same time to the San Francisco Police Department, according to Michael McCloud, fugitive taskforce commander with the U.S. Marshals Service.
Two men wanted in the fatal stabbing of a Chicago man were taken into custody by authorities in California on Friday.
"Both individuals will be held accountable for their actions, and we hope today's arrest brings some small level of closure and justice for the victim's family", Chicago Police Department spokesman Anthony Guglielmi said.
In the video Lathem said he had made the biggest mistake of his life, reports The Tribune.
"He wasn't in good spirits, but physically he didn't appear to have anything wrong", Conroy said. Lathem is scheduled to be arraigned Monday morning.
Police have not said what they believe motivated the crime.
"He knew that", Conroy said of Lathem. They will appear separately in court before being extradited to IL.
"He (Lathem) probably realized it's never going to end until he's in custody, so let me do it on my on terms". Warren's connection to the situation is unclear.
Lathem has worked at Northwestern University since 2007 where he researches a type of bacteria that causes the bubonic plague.
The pair are slated to face a judge in California before they are likely extradited to Chicago, where they will be questioned by homicide detectives. It was not immediately clear when that would happen.
Cornell-Duranleau - who had a certification in cosmetology and moved to Chicago in 2016 - was found with multiple stab wounds in Lathem's 10th-floor apartment in Chicago at around 8.30pm (3.30am BST) on 27 July.
It comes just hours after police said the murder suspects had made a donation to a library in the victim's name in a neighbouring state. The video raised concern among investigators that Lathem might kill himself. About noon Friday, he said they received further information that they were still in the area.
Lathem and Cornell-Duranleau knew each other but it is not clear whether Warren, who was visiting the USA for the first time, knew him, police said.