Half a brick was hurled through a 79-year-old woman’s window in Birstall.
Large and small pieces of glass, along with the brick, landed near the pensioner at her home in Branwell Walk between 8.40pm-8.45pm on Tuesday.
Insp Neil Money, who leads the Batley and Birstall Neighbourhood Policing Team, said: “This was a unprovoked incident of criminal damage on the home of an elderly lady who was fortunate not to be injured.
“We want to hear from anyone with information that may be able to assist the investigation.”
Call police on 101 with information.