Two Ashley Madison clients are reported to have taken their lives after hackers published their details according to police in Canada.
The police revealed the news at a press conference in Toronto but gave no further information about the deaths.
Ashley Madison's Canadian parent company Avid Life Media is offering a C$500,000 (£240,000) reward for information about the hackers, they added.
Over 33m account details were stolen.
Ashley Madison is a dating website which offers users the opportunity to have an affair.
Addressing the hackers, known as The Impact Team, acting staff superintendent Bryce Evans of the Toronto police, said: "I want to make it very clear to you your actions are illegal and we will not be tolerating them. This is your wake-up call."
Police are seeking information from members of the wider hacker community that might aid their investigation.
The breach was "very sophisticated", said Detective Menard from the technological crime unit of Toronto Police.
Cash reward
"Today I can confirm that Avid Life Media is offering a $500,000 (£t) reward to anyone providing information that leads to the identification, arrest and prosecution of the person or persons responsible for the leak of the Ashley Madison database," he added.
Mr Evans confirmed that credit card data was included in the original data dump released by the The Impact Team.
He said that investigators believed this was limited to the last four digits of the main card number.
Consequently, police are advising victims of the hack to review their accounts.
He also explained that the hack had already led to a series of "spin-offs of crimes and further victimisation".
"Criminals have already engaged in online scams by claiming to provide access to the leaked websites," he said.
"The public needs to be aware that by clicking on these links you are exposing your computers to malware, spyware, adware and viruses."
'Thunderstruck'
The unfolding of the hack was also detailed at the conference - from the moment on 12 July when several Avid Life Media employees logged in to their computers and were confronted by a message from the hackers.
This message was accompanied by music - AC/DC's "Thunderstruck", said Mr Evans.
"This hack is one of the largest data breaches in the world and is very unique on its own in that it exposed tens of millions of people's personal information," he added.

http://www.bbc.co.uk/news/technology-34044506