Relatives of the three American missionaries shot dead in Yemen have been trying to comfort themselves with the knowledge that the victims were doing what they loved.

All three of the murdered hospital workers - Kathleen Gariety, William Koehn and Martha Myers - were committed to helping others and to Yemen, their families said.

Hospital administrator William Koehn planned to retire within months

Mr Koehn, 60, had planned to retire as hospital administrator in October next year after 27 years in Yemen with his wife, Marty.

His son-in-law, Randal Pearce, said the couple had made many good friends in Yemen and he could not hold the people as a whole responsible for the killings.

"William was there doing good," he said.

"This doesn't represent the people of Yemen... This was one gunman, and that's what terrorism is."

That sentiment was echoed by Jerry Gariety, the brother of Kathleen, 53, who had been in Yemen for about a decade.

Kathleen Gariety rejected family pleas and went back to Yemen

"There are good people out there," he said.

Relatives had tried to persuade Ms Gariety - a purchasing agent for the Baptist hospital - to stay in the US this summer, but she insisted on going back to the work and the people she loved, he said.

"I give her great, great credit for the life that she chose, but it's hard to accept," he said.

Martha Myers loved the people of Yemen, and the country had been her home for 24 years, her father Ira Myers told the Associated Press news agency.

My Myers, the retired director of the Alabama Department of Public Health, said his daughter - a doctor - had helped with immunisation programmes and developed a specialty in women's health.

"She had the opportunity to talk to the native women," he said.

Dr Martha Myers first went to Yemen while still at medical school

"That would not have been possible for a male doctor in that culture. She delivered lots of babies."

He also thought of the people left behind in Jibla, the Yemeni town where Baptist Christians have run a hospital for 35 years.

"We are concerned for the people who have been getting their care from Martha and the others at the hospital. Now where do they go?" he asked.

Yemen had been a life and career choice for his daughter, 54.

"She went over when she was a senior in medical school. She decided that's where she wanted to be," he said.