The firm said that the five more suspects need to be arrested and said they are in the United States, Russia and China. It has fingered them for their roles in the 2013 attacks that were carried out by an outfit called Stophaus.
With two people already under arrest, a Dutch national and a Brit, Spamhaus wants the rest to come in and face accusations. It said that the 2013 denial of service attack was a very big one that spread from one target to another.
"The record-breaking attacks were initially directed at Spamhaus infrastructure such as websites, mailservers and nameservers," it said.
"Then, over the course of the following two weeks, the attacks escalated to targeting Spamhaus' supporting networks and services including various onternet exchanges."
The British suspect was charged last week, and according to the National Crime Agency he is 17 years old. He was arrested last year.
The antispam outfit says that it and law enforcement authorities have identified the other "peripheral" suspects.
"With two of the attackers now charged and awaiting trial, Spamhaus has hopes that the other conspirators, consisting of two United States nationals, two Russians and a Chinese national will also soon be charged," it added.
"Several more spammers and cybercrime-involved server hosting company owners were peripherally involved and at this time most have been identified by both Spamhaus and law enforcement."