Police fear a West Australian woman found dead in South Africa may be the victim of foul play, after she travelled to the country to see a man she met on an online dating service.

The body of 67-year-old Jette Jacobs, from Wagin, south of Perth, was found in a rented villa in Johannesburg on February 9.

Her money, credit cards, laptop computer and jewellery were missing.

She had travelled to South Africa to meet Jesse Omokoh, 28, whom she had met online and sent more than $100,000 to in recent years.

Mr Omokoh, from Nigeria, had made a proposal of marriage to Ms Jacobs before her trip.

Ms Jacobs sent about $20,000 to him shortly before the trip to assist him with travelling to meet her in South Africa.

Police say Mr Omokoh told them he discovered the body and it is too early to say whether she was murdered.

WA's Fraud Squad say Ms Jacobs' children tried to talk her out of making the trip and warned her it would be a scam.

Her son, who wants to be identified only as Mr Jacobs, believes his mother was murdered.

"We didn't want her to go, we tried to stop her but she pushed us away and said we didn't know what we were talking about," he said.

"We didn't understand he was a true friend and not one of those scams, and she really believed that she had someone that really loved her."

Ms Jacobs' husband died in 2002 and her next partner died in 2009.

Her son says the family is devastated as his mother was a strong woman and they believe she was taken in.

"After losing dad, mum was feeling very lonely so she went online and went to one of the dating sites and this young man contacted her and started to chat to her," he said.

"Mum, not realising what she was getting herself into, started talking to this guy.

"This was about four years ago, and in that period of time they'd been chatting quite regularly, then she decided to travel to South Africa to meet him."

A joint operation between WA Police and Consumer Protection tracks large amounts of money being sent from WA to West African countries.

A letter was sent to Ms Jacobs warning she might be a victim of fraud but it arrived shortly after she had left Australia.

Suspicious death

Detective Senior Constable Robert Martin, from the Major Fraud Squad, says the circumstances surrounding Ms Jacobs death are suspicious.

"This is a tragic series of consequences of meeting a person online, who isn't the person you believe they are, and it's a very common occurrence, alarmingly common occurrence," he said.

"We're finding that these people in their mid life to older days are falling victims to these overseas criminals who are grooming them over a period of time and then stealing their funds from them."

Detective Martin says they have saved a couple of other people from making a similar mistake.

"Fortunately we were able to get to a couple of other people involved in these romance frauds and they were intending to depart in very similar circumstances to Ms Jacobs, but we were able to get to them before they travelled to South Africa," he said.

"My warning is that unless you have met the person face-to-face you do not know what you are dealing with when you are talking to somebody online.

"It is absolutely fraught with danger and we would say don't send money to anybody that you have met on the computer.

"We also strongly urge people not to travel overseas to meet someone they have met on the computer.

"They are organised criminals and the evidence that we've gathered to date strongly indicates that the perpetrators are extremely well-organised con men and fraudsters, and we are finding that there's a network around the world and these people are operating in cooperation with each other."

Mr Jacobs is also warning others to take heed from what happened to his mother.

"Don't believe you have got someone real on the other end," he said.

"They are professionals, they are really good at what they do.

"They will use any approach to try to make you believe that they need help or they need some money; and don't go to South Africa, it's very, very dangerous."

WA police are liaising with South African police to investigate the death.