Thomas Goodwin is reported to be president of the Final Exit Network
Four people have been charged in a wide-ranging investigation in the US into an alleged assisted suicide ring.
Georgia's Bureau of Investigation (GBI) said the four were members of the Final Exit Network, charged with helping a man end his life by inhaling helium.
Police in eight other states are now investigating the group, the GBI said.
On its website, Final Exit Network says it is a voluntary, non-profit group supporting "those who need relief from their suffering today".
The group's vice-president, Jerry Dincin, said its volunteers did not actively participate in ending people's lives.
"When they choose to exit, as we call it, we just hold their hand. That's about it," he told the Associated Press.
The GBI said it arrested Final Exit members Thomas E Goodwin, 63, and Claire Behr, 76, at a home in northern Georgia after an undercover agent posed as a group member seeking assistance with his "suicide".
Two others, Dr Lawrence D Egbert, 81, and Nicholas Alec Sheridan, 60, were arrested in Maryland.
Claire Behr and Mr Goodwin were arrested in a sting operation, police say
Mr Goodwin is the organisation's president, Dr Egbert the medical director and Mr Sheridan a regional co-ordinator, AP reports.
The four have been charged with assisted suicide, tampering with evidence and violating Georgia's anti-racketeering act.
Georgian police began investigating the group after suspicions were raised that 58-year-old John Celmer, of Cumming in Georgia, who had undergone years of cancer surgery, was helped to die.
The GBI said in its statement that new members of the Final Exit Network paid $50 (£35) to join and then went through an application process.
The member is visited by an "exit guide" and is instructed to buy helium tanks and a specific type of hood known as an "exit bag", the statement adds.
Under Georgian law, those found guilty of assisting a suicide could face up to five years in prison.