Los Angeles County Sheriff Alex Villanueva was joined Monday by investigators from the homicide bureau and Chief Medical Examiner Dr. Jonathan Lucas who explained some of the steps being taken in the investigation, including forensics on the rope used in the hanging, dissecting the structure of the knot, as well as researching Fuller's medical history locally and in Arizona and Nevada where they believe he lived in the past.
RELATED: Couple who confronts San Francisco man for stenciling 'Black Lives Matter' on his own property apologizes
Investigators are also trying to identify surveillance video near the scene.
During the news conference, investigators said the only evidence found at the scene was a rope, the contents of the victim's pockets and a backpack he was wearing.
"I reached out to Attorney General Xavier Becerra and they are now going to provide a monitor and review all of our investigation to make sure we didn't leave any rock unturned," Villanueva said at the news conference.
Villanueva said he also reached out to the FBI and spoke with a special agent who indicated the civil rights division will also be monitoring the investigation.
Monday's news conference comes following mounting calls for an independent investigation into Fuller's death after his body was found last week at a park near City Hall.
RELATED: Family threatened with violence in Burlingame while wearing 'Black Lives Matter' shirts
The Los Angeles County Sheriff's Department said the cause of death appears to be suicide, but authorities are waiting for full results of an autopsy before making a final determination.
Following the news conference, the City of Palmdale released a statement, which said in part:
"The City of Palmdale will not rest until an exhaustive review of Mr. Fuller's death has been completed and justice is given to him."
VIDEO: Officials call for independent probe into death of Robert Fuller
A sit-in at City Hall was planned for 7:30 a.m. as organizers demand justice for Fuller. The group is seeking more information on Fuller's case, including the release of the 911 call and the autopsy.
With calls for police reform and protests against police brutality and racial injustice sweeping the nation, Fuller's friends are demanding answers.
On Saturday, family, friends and community members gathered at a park in front of City Hall and held an emotional rally, demanding answers into Fuller's death. His family believes he wasn't suicidal. Some in the community fear something more sinister is to blame.
Fuller's death shed light on another Black man, Malcolm Harsch, who was found hanging from a tree in Victorville on May 31. The San Bernardino County Sheriff's Department said no foul play is suspected. However, his family is also raising concerns.
Officials said they do not have a timeline on how long the investigation into Fuller's death will take.