WASHINGTON (AP) — Federal investigators have so far not found evidence that clears the high bar for federal hate crime charges against a man who has been accused of killing eight people at three Atlanta-area massage businesses, two law enforcement officials told The Associated Press.

Seven of the eight people killed were women; six were of Asian descent. The crime has stitched together stigmas about race, gender, migrant work and sex work.

Though investigators have not ruled out ultimately filing hate crime charges, they face legal constraints in doing so. Federal statutes require prosecutors to prove that the victims were targeted because of specific factors, like race, gender identity, religion, national origin or sexual orientation, or the suspect infringed on a federally or constitutionally protected activity. To successfully prosecute a hate crimes case, prosecutors typically seek tangible evidence, such as the suspect expressing racism in text messages, in internet posts or to witnesses.

No such evidence has yet surfaced in the Georgia probe, according to the officials, who have direct knowledge of the investigation into the suspect, 21-year-old Robert Aaron Long. They were not authorized to speak publicly and spoke to The Associated Press on condition of anonymity on Friday.

Advocates have said even if the shooter didn’t specifically target the victims and because some were Asian, he still could have been acting with bias against them. Three of the women died at the Gold Spa in Atlanta, while the fourth woman died across the street at Aromatherapy Spa. Four other people were killed and one was wounded at Youngs Asian Massage near Woodstock, in Atlanta’s northwestern suburbs. Their deaths come as crimes against Asian Americans are spiking.

Officials have identified those killed as: Soon Chung Park, 74; Hyun Jung Grant, 51, whom family members identified by her maiden name, Hyun Jung Kim; Suncha Kim, 69; Yong Ae Yue, 63; Delaina Ashley Yaun, 33; Paul Andre Michels, 54; Daoyou Feng, 44; and Xiaojie Tan, 49, who owned Youngs.

Both federal and local investigators are still looking into the possible motive behind Tuesday’s killings.

Most crimes are handled by local prosecutors. Federal officials may get involved when there is a violation of a U.S. statute, like civil rights crimes targeting someone in a federally-protected class — which include race, national origin and religion, among others — as well as crimes that affect interstate commerce or violent crimes involving, for example, a felon in possession of a firearm.

After his arrest, Long told police he had a “sex addiction” and carried out the shootings because he was trying to snuff out the sources of temptation, according to authorities.

Police said the gunman previously visited two of the spas where four of the women were killed and said the suspect equated the businesses to sex, and that drove him to kill. Authorities have said he may have been headed to Florida to carry out a similar attack on “some type of porn industry.”

Georgia officials said they were still investigating and everything was still on the table, including possible state hate crime charges.

In a statement Thursday, Long’s lawyer, J. Daran Burns, offered condolences to the victims’ families. He said he was working on Long’s behalf “to investigate the facts and circumstances” surrounding the killings.