Husband of Australian teacher shot dead in Kenya arrested with second man

The estranged husband of Australian teacher Gabrielle Maina has been arrested after the mother-of-two was shot and killed in Nairobi last week, according to media reports.

Ms Maina's husband, Cyrus Bernard Maina Njuguna, and another man, John Njuguna Waithira, were arrested over Thursday's shooting in the exclusive suburb of Karen, the ABC reports.

Her lawyer, George King'ori, earlier on Tuesday said the couple was in the midst of divorce proceedings in the Kenyan courts after the 40-year-old woman was granted a restraining order against her husband in April.

"She feared her estranged husband... the husband had become very irrational," Mr King'ori said in a statement.

A post-mortem examination confirmed Ms Maina, originally from the NSW town of Armidale, was killed by a single gunshot wound, the ABC reports.

Mr King'ori said the mother-of-two may have been on her knees when she was shot.

"It is our hope that Gabrielle's family get justice and know [who] committed the brutal act," Mr King'ori said.

"I have some concerns for the children...now that she is gone. I don't know what will happen to the quality of life the children were used to."

Ms Maina moved to Nairobi from Sydney in 2015 so her two sons could experience another culture and grow up near her husband's extended family, a friend said this week.

Before moving to Nairobi, where Ms Maina was head teacher at the elite Hillcrest Preparatory School, she taught English and drama for almost five years at Sarah Redfern High School in Sydney's southwest.

Australia's foreign affairs department is in contact with Kenyan authorities responsible for the investigation into Ms Maina's death.

It is also providing consular assistance to her family in Kenya and Australia.