State records show 35-year-old Binh Thai Luc served eight years of an 11-year sentence for using a gun to rob a Chinese restaurant in San Jose in 1996.
Immigration officials tried to deport Luc in 2006 after his release from prison but were unsuccessful because the Vietnamese government failed to provide the appropriate travel documents.
"On Dec. 14, 2006, Mr. Luc was released from ICE custody on an Order of Supervision due to the delay by the Vietnamese government in securing the appropriate travel documents," Gillian Christensen from ICE Public Affairs said in a statement.
ICE officials have launched a detainer on Luc following his arrest.
Police arrested Luc early Sunday morning and booked him on five counts of murder and also on a weapons charge. They haven't said why he is the prime suspect in the case.
Neighbors at the Western Addition complex where he was arrested say police broke down the back door to make the arrest.
Patsy Brown said she couldn't believe Luc was arrested for murder. It's hard to find a parking spot in her neighborhood, but Luc would hold a spot for her daughter, she said.
Binh Thai Luc's brother, Brian Luc, was also arrested and charged with possession of narcotics and ammunition and for a probation violation.
On Monday, the medical examiner's office revealed the identities of the five people found dead on Friday. The victims were identified as Vincent Lei, 32; Hua Shun Lei, 65; Wan Yi Wu, 62; Ying Xue Lei, 37; and Chia Huei Chu, 30.
Memorials for the victims have begun. Friends laid flowers outside the house on Howth Street where the five people, four from the same family, were found murdered. They bowed in a Chinese cultural show of respect for the dead.
A memorial for Hua Shun Lei was held Monday afternoon at Chinatown's R&G restaurant -- where the man known only as Chef Lei had worked for 18 years. The owner said Hua Shun, who had been a teacher in China before coming to the U.S., was getting ready to retire.
Ying Xue Lei was a software engineer in Emeryville, where co-workers described her as smart and quiet.
Investigators are starting to piece together how the victims were killed. Police have said the victims suffered blunt trauma, but they aren't entirely sure yet about the cause of death. They've said the scene was shocking in its brutality.
"There was an edged weapon involved, but we don't know the circumstances until we get that from the medical examiner," San Francisco Police Chief Greg Suhr said.
There are also unanswered questions about what the motive was behind the murders. Binh Thai Luc possibly has some gang ties.
He's been housed in a special observation section of the jail where interviews are not allowed. No problems have been reported with him.
Forty police investigators have been working on the case since Friday morning. There are multiple crime scenes inside the home and police have no estimate of when they'll be finished processing them.
Leslie Porras lives two blocks from the crime scene near City College of San Francisco. She said she's upset by the vicious killings and is anxious to know more from police.
"My parents are worried. My kids, they're nervous and scared, especially when we drive home and we see all this police here, the tape here."
Binh Thai Luc has been housed in a special observation section of the jail where interviews are not allowed. No problems have been reported with him. He could be arraigned as early as Tuesday.