Two women threatened to harm a mother's baby if she did not hand over her purse, police in Edinburgh said.
The 21-year-old victim gave the robbers her purse after one woman grabbed her by the hair and pulled her to the ground. The other threatened her.
The suspects ran off down a lane in the Gracemount area after the attack on Thursday evening.
In a separate incident, a thief robbed a 71-year-old woman in a wheelchair in Edinburgh on Saturday morning.
The victim was making her way along Pilton Avenue when a man on a bicycle snatched her handbag.
He was last seen running off towards the Royston area.
The suspect was described as white, in his early teens, of average height and build and was wearing a dark-coloured baseball cap and black anorak.
The stolen bag contained a black leather purse and the victim's glasses.
A Lothian and Borders Police spokeswoman said: "Stealing from a vulnerable wheelchair-bound woman is an extremely callous act, and we are keen to trace this youth who was last seen in the Royston area."
Police said they would particularly like to speak to a passer-by who enquired after the victim's wellbeing following the theft.
The suspects in the attack on the mother and baby were distinctive looking, police said.
The woman who pulled the victim to the ground was described as white, in her mid-twenties and had blonde, dyed hair, which was possibly black underneath.
She was about 5ft 7in tall, with a sweaty, spotty appearance and brown discoloured teeth.
The woman was wearing denim trousers with a floral pattern at the bottom of the legs and a light-coloured jacket with fluffy hood.
She wore a big-hooped gold earring in the right-side of her nose.
The second suspect was described as white, in her early twenties, of stocky build, with dark brown hair in a ponytail.
She had a couple of front teeth missing and had bad breath.
She was wearing lots of brightly-coloured make-up and had big gold-hooped earrings in both ears.
She was also wearing a light-grey coloured tracksuit with reflective stripes on it.
A police spokeswoman said: "The victim was terrorised into handing over her purse to prevent her baby from coming to harm.
"It is particularly despicable for two woman to threaten another woman and a baby, and we would appeal to anyone who may have seen them to come forward."