A California Neo-Nazi group sent messages cheering the death of a gay Jewish teenager over their message server last month.

Atomwaffen, a group who embraces a hateful ideology towards LGBT and minority groups, celebrated the January stabbing death of 19-year-old Blaze Bernstein, according to PinkNews. Samuel Woodward, an alleged member of the group, has been charged with the killing after he was arrested on Jan. 9.

“We haven’t seen anything like Atomwaffen in quite a while,” Keegan Hankes, a researcher for the Southern Poverty Law Center, said to ProPublica. “They should be taken seriously because they’re so extreme.”

Atomwaffen has allegedly threatened to cripple public water systems and take out parts of the California electrical grid, according to ProPublica. The group allegedly has up to 20 cells across the country, including in Texas, Nevada and California.

Woodward and Bernstein allegedly knew each other in high school, according to ProPublica. Woodward has pled not guilty to the charges he is facing.

“It’s sad that a young person is so filled with hate that they need to collaborate with other people of like mind and they could be doing something good,” Blaze’s mother said.