Email inventor Ray Tomlinson sent the first email using the Arpanet network NICHOLAS KAMM/AFP/Getty Images

Ray Tomlinson, the American programmer credited with sending the first email across a network and initiating the use of the "@"symbol, has died of a suspected heart attack at the age of 74. He is widely known as the inventor of modern-day email, sending the first on the Arpanet system, the internet's precursor, in 1971.

"It is with great sadness we acknowledge the passing of our colleague and friend, Ray Tomlinson. A true technology pioneer, Ray was the man who brought us email in the early days of networked computers.His work changed the way the world communicates and yet, for all his accomplishments, he remained humble, kind and generous with his time and talents, He will be missed by one and all," said a spokesman at Raytheon, the company where Tomlinson conducted the email experiments.

Tomlinson worked at Raytheon's facility in Cambridge, Massachusetts. The cause of his death has yet to be confirmed.

Vincent Cerf, a Google researcher and internet pioneer, posted condolence messages on Twitter.

Tomlinson studied at the Rensselaer Polytechnic Institute and MIT in the 1960s, and was working at research and development company Bolt Beranek and Newman – now Raytheon BBN Technologies – when he made his email breakthrough. He sent a message from one Digital Equipment Corporation computer, DEC-10, to another. The two machines were placed next to each other and connected to the Arpanet, a government-funded network that connected various research organizations across the country.

Previously, mail could be sent only to others who used the same computer. That feat was achieved in 1961 by a man named Tom Van Vleck. But Tomlinson used the @ sign to separate the user name from the name of their machine, a scheme which has been used in email addresses since.

Tomlinson's method was quickly adopted across Arpanet, leading to the swift popularity of email. In an interview to Wired magazine in 2012, Tomlinson said he now did not remember what the first message was that he sent over while conducting this experiment.

"They were entirely forgettable and I have, therefore, forgotten them. But I was satisfied that the program seemed to work and announced it by sending a message to co-workers explaining how it could be used," he said.

In 2000, Tomlinson received the George R Stibitz Computer Pioneer Award from the American Computer Museum. He also went on to receive a Webby Award from the International Academy of Digital Arts and Science, an innovation award from Discover magazine, and the Eduard-Rhein Cultural Award.

"Tomlinson's email program brought about a complete revolution, fundamentally changing the way people communicate," says the Internet Hall of Fame, which inducted Tomlinson in 2012.