BOSTON (CBS) – Organizers of a “straight pride” parade planned for this summer in Boston said they received suspicious letters, prompting large responses from Massachusetts State Police bomb squad, the FBI and fire departments in three communities. The calls came from Woburn, Salisbury and Malden.

According to sources, the letters were sent in the U.S. mail with no return address. Inside each was bible passages and colored glitter. The FBI said there is no immediate threat to the public.

“Straight Pride” parade organizer John Hugo said he and two of other members of the group Super Happy Fun America were targeted and called police.

He said Samson Racioppi called him about a suspicious envelope with powder. Hugo found a similar letter and called police. A third member of the group then found a letter as well but no one opened them.

“We, of course, called the police, I mean why would we open something like that. Even if it’s nothing in it, it’s still terrorism as far as I’m concerned because obviously it’s meant to intimidate us,” Hugo said.

Samson Racioppi, the organizer from Salisbury said, “I flipped it over and there was tape around where it’s sealed. And so all of these are red flags for me. And then I shook it and you could hear something rattling around inside. It wasn’t powder, it was bigger than powder, it felt more granular in nature, bigger than sand. I was immediately alarmed of course.”

He added that this would not deter him from organizing the parade.

According to Hugo, group members have received hate mail since the parade announcement and he said their addresses have been posted online.

The “straight pride” parade is planned for August 31 in Boston.

According to Boston Police, a suspicious letter addressed to City Hall was opened by an employee Monday. Police, along with the FBI, are working to determine if it’s connected to the other letters.

Sources tell the I-Team the City Hall letter also had a glittery substance in it.