Federal authorities are reviewing the investigations into the deaths of two men, who were each found dead and hanging from a tree, to determine if federal laws were violated, the FBI said.
The two men died in California towns about 50 miles apart.
In Victorville, 38-year-old Malcolm Harsch was found dead, hanging from a tree, on May 31, according to authorities.
"There were no indications at the scene that suggested foul play," the San Bernardino County Sheriff's Department told ABC News this weekend. "The cause and manner of death are pending."
In Palmdale, 24-year-old Robert Fuller was found dead, hanging from a tree, on June 10, Los Angeles County sheriff's officials said.
Though "initial signs seem to point" to suicide, and there was nothing to suggest foul play, officials "felt it prudent to roll that back and continue to look deeper, which is why currently the case is still deferred and under investigation," the chief medical examiner for Los Angeles County, Jonathan Lucas, said at a news conference Monday.
The FBI said in a statement Monday: "The FBI, U.S. Attorney's office for the Central District of California and the Department of Justice Civil Rights Division are actively reviewing the investigations into the hanging deaths of two African American men in the cities of Palmdale and Victorville to determine whether there are violations of federal law."
At the site of Fuller's death, nothing was found at the scene besides the rope, his backpack and the contents of his pocket, Los Angeles County Sheriff's Homicide Capt. Kent Wegener said at a news conference on Monday.
A complete autopsy was performed on June 12, Lucas said. Officials are awaiting toxicology results and are looking into Fuller's medical history, Lucas said.
"We don't have much to release at this time other than we're going to continue to evaluate the evidence as it comes in, independently make an assessment into the cause and manner of death," Lucas said.
Investigators will complete forensics on the rope and look into how the knot was tied, Wegener said. They are also analyzing Fuller's phone and will look for any surveillance video that may have captured the scene, he said.
Fuller's family said Tuesday that they are seeking an independent investigation and autopsy.
His family, as well as community members, are "enraged" that "the Sheriff's Department immediately declared his death a suicide," family attorney Jamon R. Hicks said in a statement Tuesday.
"For African-Americans in America, hanging from a tree is a lynching. Why was this cavalierly dismissed as a suicide and not investigated as a murder?" Hicks said. "We want complete transparency. To that end, the family should choose the pathologist to conduct the independent autopsy."
Meanwhile, Los Angeles County Sheriff Alex Villanueva said he would "have conversations" with the investigators in Victorville, which is located in nearby San Bernardino County.
San Bernardino Sheriff's officials said Monday that Harsch's death remains under investigation.
Harsch's autopsy was completed on Friday. "Although there remains no signs of foul play, the forensic pathologist is waiting for toxicology results before assigning the cause and manner of death," the sheriff's department said.
If you are in crisis, please call the National Suicide Prevention Lifeline at 1-800-273-TALK (8255) or contact the Crisis Text Line by texting TALK to 741-741.
ABC News' Matt Gutman, Alex Stone and Matt Fuhrman contributed to this report.