Fears are mounting that slain Australian teacher Gabrielle Maina may have been a victim of a targeted killing in Kenya.

The Australian expat was shot dead in a botched robbery in the country’s capital of Nairobi on Thursday morning local time.

It is believed the mother-of-two was walking home in the affluent suburb of Karen after dropping off her son at a friend’s home when assailants on motorbikes attacked her.

Ms Maina’s Kenyan lawyer George King’ori said the angle of the bullet wound and the marks on her skin suggested she might have been forced to kneel on the road before she was shot.

“She must have been kneeling down, and maybe begging for mercy,” he told the ABC.

“Because there were markings on her knees, showing she was most likely kneeling.”

The teacher from Armidale, New South Wales, had moved to Nairobi with her family in September 2015.

Karen police commander Cunningham Suiyanka said Ms Maina was shot in the neck on Miotoni Road at 10am on Thursday, according to Daily Nation.

Mr Suiyanka said police suspected the killers were on a motorbike because people heard the sound of a motorbike immediately after the shooting.

He said witnesses who reported the shooting also heard two gunshots.

However, detectives are yet to discover if anything was taken from the headmistress.

“She had a wrist watch and a wedding ring, which is quite expensive,” Mr Suiyanka said.

“We didn’t find a mobile phone on her but we don’t know if she was carrying one in the first place.”

Hillcrest School chairman board of governors Bob Kikuyu said she was killed while returning home after dropping her son at a friend’s house.

“It is with great sadness and shock that we are writing to let you know that Gabrielle Maina has been tragically killed whilst out walking this morning,” Mr Kikuyu said in a message to parents.

“We cannot give more details at this time as police are investigating this criminal act.”

Ms Maina was the head teacher at the Hillcrest Preparatory School – an international school situated on a 35-acre site in Karen, Nairobi.

In her welcome message on the school’s website, Ms Maina described the school as “truly international” with a large diversity of cultures and backgrounds.

“…We have built our school on a philosophy of inclusion, where every child feels a sense of belonging,” she writes.

NSW Education Minister Rob Stokes expressed his condolences to Ms Maina’s “husband and children, family and friends”.

Mr Stokes said Ms Maina had taught in a number of NSW public schools and worked as an English and drama teacher at Sarah Redfern High School for almost five years.

“Gabrielle was truly committed to her faith and her family, which took her to Kenya where in recent years she committed herself to educating young children.”

The NSW Teachers Federation said it was “deeply saddened” by the news.

“As an English teacher, Gabrielle was known for her passion for poetry as well as her work mentoring students from low SES backgrounds which included running a homework centre for students,” the Federation said in a statement.

The Hillcrest Preparatory School is reportedly set to reopen on Monday.

-with ABC/AAP