Police said a woman with her 9-year-old son in the car robbed a convenience store and fled at high speed before state troopers in Butler County caught her last night.

The woman, Debora Twyman, 37, of Saxonburg, now has been connected with four convenience store holdups in the past week.

State police said the Petrolia Uni-Mart reported a robbery just before midnight. Troopers spotted a vehicle matching the description of the robber's traveling at high speed on Route 38. When police stopped the car, they discovered the boy inside.

They said Ms. Twyman was charged with the Petrolia holdup and two others yesterday -- the Herman Mini Mart in Summit Township at 2:20 p.m. and the Honey Bear market in Butler at 7:36 p.m.

Police said she has also confessed to robbing the Co-Go's in Butler Township on Monday. Butler City police said Ms. Twyman was targeting businesses with female clerks on duty.

Ms. Twyman has been jailed on $250,000 bond. Police did not say in a press release where her son was taken.