A child was used to distract staff in a series of thefts across shops in Mirfield and Birstall.
On each occasion two adults with a child aged between five and ten entered a commercial premises, distracted staff and then stole items.
A purse was stolen which contained photos of a sentimental value on Wednesday (12) in Huddersfield Road, Mirfield, just after 1pm.
The trio then moved on to a premises on Sunnybank Road where a purse containing cash was stolen at 1.30pm.
At 4pm, in Low Lane, Birstall, another purse containing cash was stolen.
Police said the woman distracted staff, asked various questions and tried to book an appointment. As she did this the boy ran around the store while the man took the items.
The suspects are thought to be Eastern European. The woman is described as aged between her mid 20s to mid 30s and around 5ft 3in. The man is described as aged from his late 20s to mid 30s.
PC Rosaleen McCaffrey said: “I am urging shopkeepers in particular to remain vigilant when dealing with anyone on their premises and if anyone witnesses a similar incident to contact police on 101.”